PontiacBonnevilleClub.com

Hi.

Hope you and, yours are well.

You guys have me running in circles. LOL. OK.

I have a 93 Bonn SE. 175, 000, mls.

It has a warm power loss problem. Sometimes it dies. But, when warm. No power.

Now. Let me get you, to know me. OK. I'm a new member to this forum. But, not new to the forum. I've been after this obvious electrical problem for over a year. And, I'm well versed in Auto's. OK.

So. Let's cut to the chase.

This car runs great cold. You have to drive it in warm weather to get it to act up. It get's warm. And, acts like its out of fuel. Except, if you turn it off. It will restart. If you let it cool off. It goes good until it gets warm, again.

Now. I wrote. I'm new here as a member. Not new to these posts. OK.

I've been steadily looking for this problem for a year. So, lets get to it.

I've checked the battery cables. OK. Removed the plastic covers. Cleaned them. I've even checked them for voltage drop to the relay tree on the firewall. I replace the positive end to this relay tree. Just for starters.

This car cranks just fine. I'm suprised that my starter is not wore out from restarting. LOL. Tough starter.

Now. Before you get all excited thinking you have an answer for me. I'll elaborate some more. Those groud pin connectors running under the floor trim look new. I unplugged them. Checked them. OK.

Now that I've covered most of your common repair responses. Let's move on.

Since, it obviously appears to be like a overheating fuel pump. I changed that. And, before that. I put on a new fuel filter. Still. I'm not getting an answer. Still gets warm. Still loses power. Like no fuel.

OK. On I go. I'm very confident. OK. This car has no codes. I get another PCM. Another control module. A crank angle sensor. A crankshaft sensor. A fuel pump relay. I tried two fuel pump relays. I've check the Catalytic convertor for a restriction. Not that. I've beat the muffler thinking it has an intermittant restriction. I've unplugged the MAF. It should substitute. No help. Unplugged the coolant sensor, the TPS, The IAC. So, much. I probably forgot about all things I've unplugged that didn't make a response.

I have pulled the injector harness and, gone through it. Yes. I thought that would fix it since the insulation was melted off the wires. Where it raps around the front of the intake manifole. Now, maybe you're wondering if I fixed that right. Well. At this point. I'm skeptical. But, I know how to remove pins from connectors. And, I use heat shrink. So, it looks good. And, I have a nicer one. Salvage. But, I did get another one. I havn't installed it. Because. Since, the repairs to the old one made no difference. See, where I at with that??

As, for the harness to the CPS. I havn't tore it down. It's looks real good. No oil. I've messed with it a little. Didn't make any difference.

I've spent quite a bit of time. And, learned alot about this auto. And, do appreciate this forum and, it's participants. But, I'm at a loss as to why, all the things, I have done. Have not solved this problem. I'm persistant. OK. I like this car. This should be an obvious easy to fix electrical problem. Not, one that just has about 100 answers. I have a solid symptom. It warms up. It won't go. It might die. It always restarts. But, until it cools off. It's a sputter bucket. With backfires in the intake and, all.

And, it won't die when you open the shrader valve at the pressure gauge hookup. Just spews fuel every where. No power.

OK. I'm not wanting to offend anyone. But, the most common responses that this forum has provided. Have not phased this problem.

This is specific. OK. If, you tell me to check it. I will. But, I assure you. I've checked about everything. And, I've been around the block on many problem child electrical problems. Doesn't make sense that a consistant heat related problem is in the harness, unless it's damaged or, oil soaked. And, like I wrote. I've been looking at this forum. OK.

Give me some new ideas. Please. Or, explain why the repair you recommend should fix this problem. I can see the Postive cable to the firewall relay box being a problem if it's corroded. But, it's clean,. I cleaned it. Checked. Even, cut off the end and, put on a new connector.

Ok. Enough. I'm going in circles, again.

As, an experienced auto tech. I know. If, I take this to a shop. LOL> Good Lord. What are they going to find?? And, expect me to pay for.

I can fix it. Easy. I just need a real answer.

I can expand any question with more specific information. But, please. Unless, you are almost positive about your knowledge of this specific problem. Don't throw up clean the Battery cables and, check the floor grounds. Or, what's the fuel pressure. And, yes. It has a new Crank angle Sensor. I had to buy the puller to change it. Freaking crank bolt is tight on that there 38.00.

Anyhow. It got warm today. I figured the Crank Position Sensor would have fixed it. But, it didn't. It's sick upping again. So, I'll go back out now. Get it warmed up. Maybe slap the PCM around. The 2cnd PCM. See if it's got a problem. If you think that this heat related problem is a specific electrical open when this car gets warm. I'm sure curious to know what heat has to do with a bad connection. Don't get me wrong. For every rule there's an exception. But, as a general rule. Heat doesn't cause a bad connection. As for over heating do to open connections. I get along with that. I've checked the Battery cable to the junction box. And, the tree grounds under the carpet.

I'm going to find this problem. It's getting warm. And, it is easier to make it act up. Guess, I'm going to have to go out there and, heat her up. And, start wiggling things. It's a her. She's being a B. LOL.

This car runs seriously great until it decides to not go. And, it's getting more consistant. The more I replace/repair. The less time it takes to start acting up. Or, maybe that it's just been warmer the last few days.

God Bless,

Chris

Have you checked the coils, plugs and wires? Also, you said you cleaned the positive battery terminal. What usually happens is that it corrodes on the inside, where you can't see it, and goes bad. I'd replace that while you're at it. Have you had a scanner on it when it does this, to see if any parameters are out of whack?

What method did you use for checking the cat for a restriction?

You mentioned that you checked battery cables, but what about the battery itself? Have it load tested, just to make sure. Mine had the terminal literally fall right out of the battery once.

Check your spark plugs and spark plug cables, and I'll say x2 on the coils. If your car is no go, find out which of the "fuel + spark" pair you're missing, because if you have both, it should go.

Thanks for the prompt replies.

I've already typed about a book of a response. LOL> And, it got ate. I must have hit the wrong key.

I've gone through the Battery Cables. I'm well aware of the GM cable corrosion problems. These problems plague all GM's. Especially, if you have maintenance style battery or, over tighten the terminal bolts.

The Battery is good. The cables are good and, clean.

Cat was checked at a good exhaust shop with a back pressure test. Usually a free test at an exhaust shop with a good reputation. I have no reason to suspect exhaust restriction. It backfires into the intake. Doesn't act like a clogged pipe. No hissing either. Hissing is the most common symptom. And, I know that it reads like a possible exhaust restriction. It isn't restricted. I've opened the pipe up. Loud it is/was. I've repaired many auto's with restricted cats. And, a few that's had intermittant muffler restrictions. From partial to complete blocks. None of them ever backfired into the intake. Not once. It backfires into the intake. Because it's lean. It sort of acts like a carburated engine with no choke on a cold morning. Except, pumping the gas pedal doesn't help. That's really a pretty good description of the problem. Except it is obviously a closed loop problem.

I've read the article about the coils. I've changed many. On alot of cars. DIS Rocks. I get used AC coils at a pull it yourself salvage yard for 3$ a coil. I use my Snap On Digital Volt/Ohm meter to check them. I currently have six. All. pass and, are in close range with the others I have. I've switched them several times. I switched the control module, too. Got a brand new one off of a 93 Buick Lesabre. All the new module did for me was take my over rev cut off down to 2800 RPM. None of this has changed the problem. It's not missfiring. It runs great then acts like it's out of fuel. It will only idle when this happens. Sometimes it will die. After turning off the ignition. It will start back up. And, run as long as it has time to cool. That may be confusing. It's variable according to heat. It acts up sooner and, longer on warmer days. It's not overheating. Both Fans work. AC works. And, it's full of coolant. Plug wires are easy to check. Just ohm them and, look at them. All oil soaked ones toss. If, swelled toss. If, more than a 1000 ohms an inch. Toss. I have the test plug, too. All coils and, wires fire across it. It has a 25000 ohm gap. Everything tests good. Every thing in this area has been replaced. It's not an individual firing problem. This problem affects all cylinders at the same time. I've look at the coolant sensor. It's passed all test I've done on it. I've not been able to check it when the car acts up. Except. I've unplugged it with little change. It just sets off my SES light.

It's got Platinum plugs with less than 10,000 mls. on them. They all hit good. Easy to find a miss with a test light. Ground the plug wire with it. It will make that cylinder miss.

I have not had a scanner on it. I don't work in the field anymore. But, I've scanned many autos. Scoped them, too. Just to see an answer, except for spending alot of money buying another tool. All voltages are checkable with my meter. Tell me which sensor you suspect. I'll check it. I've switched the PCM. It's a Calfornia Prom. No Change. Still does it. I've rebuilt the injector harness. Something. I highly suspected. Since, it had about two inches of missing insulation from the injector wires where they wrapped around the intake manifold. No Change. And, these wires were touching each other. Not anymore. It does act like it could be a injector dwell problem. Like somehow it can't fire them.

It wouldn't hurt my tools to have a newer scanner. But, I don't believe I've actually solved a problem like this using one. Just makes it easier to read the sensors. As for the service mode test. Yes. I'd like to run that. It usually leads to a faulty PCM or, a open wire feed. Such as a ground or, power feed. These test I will do soon. I have to get a wiring diagram. I usually get them at the Library. Mitchell. But, The library has lost the manuel they had. If, anyone has a complete wiring diagram for the 93?? I'd love to have a copy.

I highly suspect a ground/power feed problem. I have to go get some jumper wires at radio shack to check that. Like a missing firewall ground. I thought it might be the fuel pump relay overheating. But, I've changed that twice. No change. BTW. That's in the right kick panel on mine. Not under the hood. I don't see the fuel pressure regulator being a problem of this magnatude. I've change several of them. But, none of them caused enough fuel pressure problems to hardly have a symptom. If, you have low pressure do to a regulator. It's only as low as the max vac pressure. I've never seen a tempurature related fuel pressure regulator problem.

I'm going to get my fuel pressure gauge out. Even, though. I'm sure the pressure is fine. I changed the Fuel pump. Good maintenance on a car with this many mls. anyway. It did not make any difference. And, I suspect it had already been changes. Since, the Baffle housing was missing from around it. It obviously has good fuel pressure most of the time anyway. So, overheating or, worn out fuel pump are not indicated. Restriction of the sock is not indicated. I've had this tank out twice. It's clean. I've been looking at this beast for a long time. I don't drive that much. I usually have to run it for at least a half hour to get a symptom. The beginning of the symptom starts with low full throttle power after about 20 minutes of drive time after full cooldown/overnight. And, expands to no power at all after a little more drive time. Stop. Take a break. Like eat lunch. And, it cools down some. Runs for a little longer and, starts doing it again. So, cold mode uses the most fuel. It runs great until driven for at least 20 minutes. Restarting warm can get you a few mls of power back. Like pull over on the side of the highway. Turn it off. Let it set a couple of minutes. Restart take off. It has power. Then a couple more mls. It will just idle. So, if you get out on a long trip. It can be very annoying.

If, you've taken the time to read all of this. The whole post. Hopefully it was worth it to you. Thanks for the replies. I read them and, appreciate them. The replies are about real problems. And, well worth looking into. Very costly to have done. But, very good things to know about these cars. I would recommend that anyone having any type of electrical problems with any Bonnieville/Lesabre know where the grounds are under the carpet. And, know how to test coils and, plug wires. And, to know about GM's battery cable corrosion problems. Simple stuff.

The chance that a part that has been changed by me on this car being the problem are slim to none. This is like a missing ground is causing the PCM to overheat. Or, has been overheating 2 different PCM's or, 2 different control modules.

The only other thing right off the top of my head is I havn't changed the IAC. LOL.. Doubt that will do it. Since, when it acts up. The only thing it will still do is idle.

It acted up yesterday. It was 75. I've not had any problems on days below 40. But, it's going to cool down again. May be a few days before, I can get it to act up. And, I'm going to be gone for the next 3 days. When, I get it to act up. I'll check the Fuel pressure. Again. I doubt it will be bad. And, start jumping wires to verifie my grounds.

About, the grounds. Every electrical device on this car works fine. No dim lights. Fans run good. All of it. Gauges work great. I replaced the oil pressure sender. Works fine. The only other problem is the light switch reostat. That's common. Just spin it and, the dash light brightness works fine. They get dirty with age. It's been hit in the Right front. I checked the fender ground. I've looked at the ground at the Control module. I'm going to start grounding things. With jumper wires. Easiest way to find a open ground. Make a new ground. I've had problems like this on older GM's. That caused them to fall flat on thier face with the Computer controlled Carburators. Ground wires can break and, go open. I've really thought that the repairs I've made on this car. Every repair when, I made it was the answer. Because I've repaired plenty. But, still this problem clings worse than snot. Like an open fire wall connector wire.

God Bless,

Chris

SO when you have the problem and it won't run, and you're forced to wait before restarting it, I take it then that it does not restart unless you wait. At THAT time, do you have both spark and fuel at the cylinders? You didn't answer that yet.

Oh.

But, I did answer that.

It rarely dies.

I just won't go much above idle. Zero power. Every once in a while. As, you have to pull over, because you can't maintain your speed. It might die. The only way to get it to get power back, is to turn it off and, restart.

So, in the situations I've been in. It goes like this. It runs fine for a while. And, when it starts. I turn it off while still coasting. Without locking the column. After it's going to slow. I kick it into neutral. And, restart. It regains power. For a very short time. So, I'm letting the air flow from coasting flow in. I rarely pull over except to get out of everybodys way. And, coasting cools it off faster than sitting. Or, maybe it just gets me there quicker. LOL> It actually, runs longer if, I coast between shut offs.

Anyhow.

I had it out there in the yard running for 2 hrs. today/this afternoon.

Checked the floor pan ground tree again on the left side. Clean as a new one. Checked 3 grounded wires from the trunk area. Found the othe 3 ungounded wires in the connector. With a test light. Installed the steal tree plate. Checked for ground on all the wires after that with my test light. All show to be grounded. Check the ground by the E-Brake pedal. First time I've noticed that one. Checks good.

Pulled the back seat out to listen to my fuel pump. It's humming steadily. Cars running great. It sort of acted up a little for a minute or, so. Heard the pump change it's sound. Went from a steady whir to a on off on off type sound. Turned it off. Restarted. Drove it off to the store. Ran great. Got me a 4 pac. Ran great back. Of, course today. Is only about 50 degrees. May not be warm enough outside to recreate the situation. And, I'm not driving it all day. I was looking at the wires at the firewall connector, too. They were touching the inside back of the fender. So, I pulled them off of it. I was also listening to my purge solenoid clicking constantly at idle. I've unplugged it when it acted up. Didn't make any change. Rechecked the fender grounds. Looked at a green single wire connector by the battery. That doesn't appear to do anything. Maybe, has voltage on it. But, it's not 12 volts. I'll recheck it with my meter instead of a test light.

I do have the California PCM in. And, my Rev limiter appears to be cutting me out at 3500. So, my early loss of power statement may be inaccurate. What that means is. I rarely get into it. So, I've notice when I do. It starts limiting about 3500. That's with the pedal down. Full throttle. I'm not sure if it's because of the PCM. I'll have to start it cold. And, haul it. See what happens. Like I wrote. I really don't get into it often. My other PCM would not kick out until 5000 rpm. So, I'm looking into this. I'm not sure which part controls the RPM> So, this might be a clue. I changed the control module. And, it would start limiting a 2300. I did notice that. I changed it back./ And, it would scoot. Then, I got the California PCM. And, well. I don't know if that's why it's holding me at 3500. I still have my other PCM. I have to switch it back, to see. And, or, just check it cold Monday. The Control module did come out of a buick. And, yes. I know about Proms. The total no power to just being able to idle when warm has not changed with the changing of these 2 parts. Just the rev limit cutout speed. Or, what appears to be that. Like I wrote. I don't get into it that much. And, havn't had the Cali PCM that long. I went about 40 mls. in it on a warm day about a month ago after I changed the PCM. Running fine. And, it started. Just like after I changed the Control module. The Crank Position Sensor. The Fuel Pump. Repaired the Injector harness. Cleaned checked and, made the unneccessary battery cable end replacement. After checking the floor ground trees. Changing the fuel pump relay. Changing, Rotating and, switching the relays under the hood. Changing the Cam sensor. I may have left a couple things out. But, not much. I'm going to start running grounding jumper wires monday, if it's warm enough.

And, when it happens. Unplugging things doesn't help. Like the MAF, TPS, Ect. They are supposed to substitute. And, unplugging them when it's not happening. Well. It's like you didn't unplug them except the SES light comes on.

I am going to my Mom's in Arkansas. This weekend. So, I won't be able to do anything else till monday, on the car. LOL. Except, maybe check this post. That's if my Mother doesn't expect me to work on her steel horses or, help her with her PC.

God Bless,

Chris

So when you described the problem as being that your car loses power and you have to restart it to get it back, you weren't meaning "the car goes dead" by loss of power, right? You mean the engine is still running the car is still on, but you press the go pedal and you aren't going anywhere, right?

I misread the "loss of power" as "Power Off."
Your engine doesn't actually shut off at all, correct? Meaning you have both spark and fuel, right?

-Mark

Have you checked or swapped out the ICM (ignition control module) under the coils?

myfirstbonnie wrote:Have you checked or swapped out the ICM (ignition control module) under the coils?

I had the same problem over the summer, power loss when warm, rough idle too.

It was the ICM, the piece under the coils. Id clean the ground to the ICM, too.

After all the books that were posted, have you checked the crank sensor at all? Sometimes those get really fussy when they get hot and cold

Wow... I actually read all your post(s) and yes, you DID replace the crank sensor.

Are you aware of the PCM ground that is under the ICM? The plate (the ICM mounts on) is mounted to the motor on 2 studs on the engine (they face the battery). One stud is the ground point for the battery. The OTHER is where the PCM gets its ground. There are 2 nuts on the stud; 1 holds the plate to the motor; the other, outer, one holds the ground wires. I have encountered a problem on mine where, if the inner nut is not torqued down, it will allow wiggle in the PCM ground, even if the outer one IS torqued.

If that's not it, is there any way you could see/monitor your fuel pressure, driving, as the engine slows down?
I have experienced a similar problem (on a non-related vehicle) due to a fuel line feed restriction; which was actually different, being speed related. In my garage, etc., the fuel pressure would be fine, since it was a flow problem.

Bugsi wrote:So when you described the problem as being that your car loses power and you have to restart it to get it back, you weren't meaning "the car goes dead" by loss of power, right? You mean the engine is still running the car is still on, but you press the go pedal and you aren't going anywhere, right?

I misread the "loss of power" as "Power Off."
Your engine doesn't actually shut off at all, correct? Meaning you have both spark and fuel, right?

-Mark

That's the ticket.

It will only idle. No accelerator response except it will backfire into the intake. It might die if you keep holding the throttle down. Turn it off. It always restarts. Maybe the power returns maybe not. If, you leave it off for a couple of minutes. It regains power for a short period of time. So, you can get back on the road. But, since it's still at operating temperature. It usually starts acting up again in a very short period of time. Let it cool down completely. Runs like a new one. Till the temperature is at the point to make it act up again.

God Bless,

Chris

myfirstbonnie wrote:Have you checked or swapped out the ICM (ignition control module) under the coils?

Yes.

Got a new salvage from a 93 buick. All it did was change my rev limit Rpm. Car ran fine till it reached the temperature that it acts up at. Didn't change the problem at all. Ran great cold. But, would rev limit about 2500 instead of 4500. Got warmed up. And, hello. I'm still here. No change in the actual problem I'm chasing.

God Bless,

Chris

What did Silverbullet's car do when it got warmed up? I can't remember if his died totally or just lost power. His was a bad fuse connection somewhere...? Just a thought.

I caught something early on here just now.

Platinum plugs (particularly bosch) are a known problem in waste-spark ignition systems like ours. Go copper or irridium. That could still be part (or all) of your problem. Even if it isn't, it will be in a short period of time.

bobfather99 wrote:

myfirstbonnie wrote:Have you checked or swapped out the ICM (ignition control module) under the coils?

I had the same problem over the summer, power loss when warm, rough idle too.

It was the ICM, the piece under the coils. Id clean the ground to the ICM, too.

Ok.

I'll check it.

But, It's the engine ground. Not just for the ICM. It grounds the starter. And, everything else on the engine. I've tried another ICM. I cleaned the top of the plate below the ICM. I guess the plate mounting for the ICM could be dirty. But, the test light check of this plate was bright. I get a bright test light ground check every where I go. Before, and after cleaning all ground points. The other wire at the Ground point you write about goes to the RF fender. It test good. I have had no corrsion at all at any ground points except, I clean the Battery cables. And, there was very little corrosion at the battery cables. I will remove the coils, ICM, and, this plate. Remove the engine ground. Clean it. Clean the bolt that bolts it to the engine. Clean the plate. Not, sure that will help. But, I'll give it a shot. As, soon as it's warm enough. It's 21 outside now. Possible icestorm coming.

It's very factory. And, by that. I mean it's clean and, never had anything done to it by anybody but, me. I did get a socket on the ground bolt you are referring to. It didn't break loose with less the 20 lbs torgue. The nut to the harness guard came loose. Not the stud bolt. I'm sure it's still factory lock tighted in. This car has not corrosion problems to speak of. All grounding points checked, look new.

But, I'll remove the ICM plate and, all. So, I can clean the whole assemble and, engine ground. When, it warms up enough. I've been in this area already. ICM mounting plate was not loose. Test light ground check with test light was good and, bright for the mounting plate.

Cheap repair if that's the problem. Worth a shot. I may dig down to the CPS harness when I do. Check it out. But, this harness is clean and, oil free.

Thanks,

God Bless,

Chris

Christopher1watson wrote:
The other wire at the Ground point you write about goes to the RF fender. It test good.

Chris

There should be 2 black wires on that one. One goes to the fender, and the other goes to the PCM. Anyway that's the way it is on my 93. 2 wires on there also make it a little tougher to tighten down good. They want to slip. Anyway.. later

tripscarcare95 wrote:After all the books that were posted, have you checked the crank sensor at all? Sometimes those get really fussy when they get hot and cold

Yes.

10 days ago. The old one looked pretty rough. Rotton plastic. It's has a brand new Borg warner on it now. Connector and, wires looked fine at the sensor. No oil. Nothing. I twisted it a little to maybe eliminate wires inside the harness touching from rub through. Balancer is looking rough. Trying to get a newer cleaner one. Found a nice balancer. But, I broke my half inch extension trying to break the crank bolt loose. Had another one ready to remove. But, I could only get 2 of my Balancer puller bolts in it. One of the bolt holes was blocked out inside the balancer. So, if you are after a balancer, too. Make sure you can get all three puller bolts in it before you waste your time breaking the crank bolt loose. I still have not completely removed the CPS harness. I may do that soon. It's freezing outside. I have a real nice salvage injector harness. I may tear it down and, install it. I did go through and, inspect the injector harness. Made profeesional repairs to it that I was sure would fix the problem. No Change. I did this over a year ago. When the problem reared it's ugly self. That's why, when I was in the salvage yard. I pulled a real nice looking one. It's in my parts pile for it.

So, yes. It has a new one. Did not change the problem in any way. I do not ever experience any cold driveability problems.

God Bless,

Chris

93RedSled-SSE wrote:

Christopher1watson wrote:
The other wire at the Ground point you write about goes to the RF fender. It test good.

Chris

There should be 2 black wires on that one. One goes to the fender, and the other goes to the PCM. Anyway that's the way it is on my 93. 2 wires on there also make it a little tougher to tighten down good. They want to slip. Anyway.. later

I have looked and, test lighted at this grounding point.

Input ground comes from the main engine ground. It has 2 ground wires leaving out of it. With the engine ground being the input. I've test lighted all 3. Good and, bright. The bolt is tight. Can't budge these wires. None of them. Ground point is clean and, corrosion free. Easy, check though. If, I don't break a ground wire getting it a part. Won't be a problem to reverifie. All my lights, fans, and, everything else up front are working fine. I checked ground wire with the connector heading towards the firewall visually and, with a test light. Got a good bright light through the insulation after the connector. Thought, that one went to the PCM. It comes straight of the ground at the battery.

I'll pull the ground you write about. I have some body damage around the battery area. Dealve into the harness around that bent metal. I repair the marker light wire/Harness when I fixed the damage. But, all the other wires to the headlights and, horn looked fine.

God Bless,

Chris