Will not start

MOTORCAR222

MEMBER
1997 DODGE RAM
5.2L
V8
257,098 MILES

Truck was running fine but decided to tune up. Wires, plugs, cap, and button. I also installed new IAC and bank 1 sensor 1 02. Truck started immediately and idles perfectly. But it wouldn't rev up past 1,200 RPMs. This went on for a day or so then this morning it fired right but when I tried to give it gas it cut off. Now only cranks and if I hold pedal to floor tries to crank and backfired through intake.

5 Replies

KASEKENNY

MECHANIC
18,907 POSTS

So, if this was not doing this prior to replacing all these parts, the only option we have is to go back over the parts that you changed and make sure you didn't cross any spark plug wires and they are in the correct position.

https://www.2carpros.com/articles/engine-backfires-while-running

We need to pay particular attention to the firing order which I am posting below.

Basically, we need to make sure we put the wires in order going clockwise around the distributor because there are a lot of OEMs that go counterclockwise.

Also, if you have the parts that were not causing an issue, I would suggest we start reinstalling them one at a time until we find out what may have been causing the issue. Clearly the plugs are most likely fine as they are not causing the issue.

Please run through this and let me know what questions you have.

Thanks

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Wednesday, March 16th, 2022 AT 7:18 PM

MOTORCAR222

MEMBER
4 POSTS

I did that with old parts still the same. Vacuum gauge today showed a steady 11 which book says valve timing. If you let idle long it puts off a great amount of heat on the passenger side.

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Wednesday, March 16th, 2022 AT 7:58 PM

KASEKENNY

MECHANIC
18,907 POSTS

Correct. If you, have it steady 11 inches, then that points to a timing issue. The intake valve is late.

So, if this was not an issue prior to replacing these parts then we have to suspect something caused the PCM to alter the timing or it somehow is not in time any longer.

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Thursday, March 17th, 2022 AT 5:30 AM

MOTORCAR222

MEMBER
4 POSTS

Mr. Kenny, I got the #1 piston to top dead center and I took the cap off and it points to number 1 on cap. I'm baffled. Maybe a driver in computer could have gone bad. I'm going to do compression check in the morning. I appreciate ya sir.

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Thursday, March 17th, 2022 AT 12:45 PM

KASEKENNY

MECHANIC
18,907 POSTS

Yes. That is what I would think. More than likely this is a perceived issue that is causing the PCM to think the timing is off.

If you have a scan tool that can monitor this, you should be able to check the PCM to see what it says the base timing is.

I agree that if the compression is correct then the timing is most likely okay.

Thanks for the update.