3800 intermittent slow cranking when warm after ICM replacement

[Jason06lucerne]

This issue still continues with my car.

I now have 2 things to take away from this thread:

1. Check the grounding of the starter and the solenoid.

2. Check the wiring harness from the ICM to the cam and crank sensors.

A year or so later, my car continues to start, with good performance per the voltmeter, and does this every now and then.

Well I guess I’ll update the slow crank came back today I also noticed a coolant leak on right side of engine if coolant is getting into a cylinder would it cause this issue as it’s only intermittent I have no smoke coming out of engine but I feel it might be similar to hydro locking symptoms now

 

[Jason06lucerne]

Has the UIM Or the LIM (gaskets) ever been replaced? The symptoms you mentioned sound like coolant in the combustion chamber. In addition, if the battery has never been load tested, now may be the time to have that test performed.

can this happen intermittently if the intake gasket is leaking internally I have noticed coolant on my right side of engine I replaced gaskets a year or 2 ago but they are cheap plastic

 

[mbook]

Did you find your issue im having the same exact problem after replacing my icm

Ok, the problem on my 3800 of intermittent slow crank when warm after coil pack & ICM replacement has been solved. Here is what happened.

Quick review of background. I had given up on finding a solution because it seems to baffle everyone, including me. Thought I'd have to live with it. Now I have known that the throttle body needs cleaned because it sticks the 1st thing in the morning frequently and has done that for several years. Once you tap the throttle and break it loose it was always perfectly fine the rest of the day. But it is hard to get mechanics to try to solve problems they can't see unless you insist. I mentioned the sticking 2 or 3 years ago to my mechanic and it seemed fine to him –of course it would unless he took it home and let it set overnight– and he ignored what I'd said. I watched a mechanic clean a 3800 throttle body once and I know I could do it myself, but I didn't think it a good idea to do it like a trained monkey. What if a sensor goes bad during the process, etc.

But last month the car would intermittently die a time or two after 1st starting it. One time I could see some vapor or smoke rising from under the hood. I figured the throttle body issue might be getting worse. So I hustled it to the same mechanic who did the ICM, since I didn't think the slow crank issue was his fault and he is close to where I live. But I told him: "look, whatever you find, just clean the throttle body in the process because I know it's an issue at least for the sticking throttle. I know it can cause other issues as well. You won't feel the sticking throttle, but just humor me."

He checked it over and said it had a bad fuel pressure regulator. He replaced that and he cleaned the throttle body –I've no idea whether he would have or not if I hadn't asked– and sure enough after that no throttle sticking in the morning whatsoever.

But after replacing the pressure regulator and throttle body cleaning, it not only fixed the problem with the start/die issue but also fixed the intermittent slow crank when warm issue. I've no idea why, and I don't think he does. Why did the problem begin after ICM replacement? Was it the fuel pressure regulator or throttle body clean that fixed the intermittent slow crank when warm? Or could it be the issue was solved by unplugging the battery for a time that reset something? No idea. You be the judge. But the Buick is back to its old self without that annoying issue. I call that a win.

 

[Jason06lucerne]

Tan

Ok, the problem on my 3800 of intermittent slow crank when warm after coil pack & ICM replacement has been solved. Here is what happened.

Quick review of background. I had given up on finding a solution because it seems to baffle everyone, including me. Thought I'd have to live with it. Now I have known that the throttle body needs cleaned because it sticks the 1st thing in the morning frequently and has done that for several years. Once you tap the throttle and break it loose it was always perfectly fine the rest of the day. But it is hard to get mechanics to try to solve problems they can't see unless you insist. I mentioned the sticking 2 or 3 years ago to my mechanic and it seemed fine to him –of course it would unless he took it home and let it set overnight– and he ignored what I'd said. I watched a mechanic clean a 3800 throttle body once and I know I could do it myself, but I didn't think it a good idea to do it like a trained monkey. What if a sensor goes bad during the process, etc.

But last month the car would intermittently die a time or two after 1st starting it. One time I could see some vapor or smoke rising from under the hood. I figured the throttle body issue might be getting worse. So I hustled it to the same mechanic who did the ICM, since I didn't think the slow crank issue was his fault and he is close to where I live. But I told him: "look, whatever you find, just clean the throttle body in the process because I know it's an issue at least for the sticking throttle. I know it can cause other issues as well. You won't feel the sticking throttle, but just humor me."

He checked it over and said it had a bad fuel pressure regulator. He replaced that and he cleaned the throttle body –I've no idea whether he would have or not if I hadn't asked– and sure enough after that no throttle sticking in the morning whatsoever.

But after replacing the pressure regulator and throttle body cleaning, it not only fixed the problem with the start/die issue but also fixed the intermittent slow crank when warm issue. I've no idea why, and I don't think he does. Why did the problem begin after ICM replacement? Was it the fuel pressure regulator or throttle body clean that fixed the intermittent slow crank when warm? Or could it be the issue was solved by unplugging the battery for a time that reset something? No idea. You be the judge. But the Buick is back to its old self without that annoying issue. I call that a win.

thank you I will definitely try this tomorrow morning 🙏

 

[Jason06lucerne]

Tan

thank you I will definitely try this tomorrow morning 🙏

What pressure sensor did you replace along with throttle body cleaning

 

[mbook]

Tan

thank you I will definitely try this tomorrow morning 🙏

On the throttle body cleaning, when I saw this done a few years ago the guy removed it, sprayed some type of cleaner on a rag, and carefully wiped off the carbon with the damp rag. I hear you don't want to spray cleaner into the throttle body because it can damage the sensors on it.

 

[mbook]

What pressure sensor did you replace along with throttle body cleaning

My mechanic did it. I suppose it was the fuel pressure regulator. On the fuel rail I think.

But ... sigh. I have some sad news to report. The slow cranking is back. I've no idea why it disappeared for 4-6 weeks after the work that needed to be done and then came back. But come back it has. I'm just going to have to live with it.

 

[HotZ28]

When you mention "slow cranking" are you talking about the starter not turning the engine fast enough, or is there a delayed start if the starter is spinning & working normally? 🥱

 

[Jason06lucerne]

My mechanic did it. I suppose it was the fuel pressure regulator. On the fuel rail I think.

But ... sigh. I have some sad news to report. The slow cranking is back. I've no idea why it disappeared for 4-6 weeks after the work that needed to be done and then came back. But come back it has. I'm just going to have to live with it.

Are you leaking coolant I’ve been told the intake might be leaking into a cylinder

 

[mbook]

Are you leaking coolant I’ve been told the intake might be leaking into a cylinder

No not leaking coolant. I had the intake gaskets replaced a while back.

 

[mbook]

When you mention "slow cranking" are you talking about the starter not turning the engine fast enough, or is there a delayed start if the starter is spinning & working normally? 🥱

Starter not turning the engine over fast once in awhile. Spins a revolution or a half one and then virtually stops, but then pushes past and spins and starts. Just like an old car with timing too far advanced.

 

[mbook]

I have to say though after coil pack and ignition module replacement it is pretty rare for it to do it. It was maybe 1 out of 5 times when warm. After the throttle body cleaning and fuel regulator or whatever that was done I thought it was over. Though I can see it still does it now, at this point I'd say it does it very rarely. Maybe 1 out of 20 times or perhaps more, and never when cold but only when warm. These are all just observations. I've no idea what any of the work had to do with this issue directly since it is such a weird problem.

 

[mbook]

I frequently watch a YT channel with Eric O. from South Main Auto in upstate NY. Just watched a long video named "Poor Running Buick LeSabre" and he went very deep into how to troubleshoot 3800 ignition issues. In that video he said he is "OEM only" on the ignition parts. The brand of ignition module (and presumably coils) used on my Regal is called 'Standard'. He said all the non-OEM brands he considers Chinese junk, and he specifically named Standard as one of them. So my guess is that if the mechanic had used Delphi ignition module and coils I wouldn't be having this intermittent problem. I don't think it is possible to actually troubleshoot such an intermittent issue.

 

[Allure 2008]

Wow I’ve been chassing the same problem on my 2008 Buick , and it started happening after replacing the icm with a standard too ! I have brand new battery wires plugs coils and still does it once every about 10-15 cranks but always starts , I’m starting to wonder if it’s a problem with those standard icms after reading this thread