FEandGoingBroke

Customer brought me his piece of FarmVille 97 Silverado with a 5.7.
He said he replaced the water pump the timing chain, the distributor, the crank sensor and the cam sensor.

There’s a P 1345 (In GM vehicles, improperly installed valve timing chains or defective crankshaft or camshaft position sensor)

there are no other codes present. I replaced his cam position sensor inside of that new distributor and I removed his new composition sensor that he bought from Amazon or wherever..

He told me he thought he had an intake manifold, vacuum leak I replaced the upper manifold gasket, it started and ran with the exact same issues. I sprayed everything down with ether. There was no vacuum leaks located whatsoever.

The engine surged a lot. I verified the timing with my baroscope on the compression stroke at Top dead center to the timing pointer on the rotor straight at number 1- a degree or two. At that point I did the hillbilly fix of slotting the hold down so I can turn the distributor square onto the center of the number one which is about 2° and the truck runs better at idle but when you hit the throttle it’s like crap again so I’m looking for suggestions that would keep this cam sensor. Failure code coming back. Under fuel pressure and over. Fuel pressure is not going to affect the code that says P 1345.

So I’m looking for suggestions and now that you can read it in proper English. Let’s see what you guys have for me :-) thank you

FEandGoingBroke

I was voice texting that whole thing, but you get the general idea of what I was trying to say I’m not gonna go back through three paragraphs just to correct little grammatical errors from this dragon software failing me lol

mountainmanjoe

If people can't be bothered to use legible English, why should others be bothered to read it? 🤷‍♂️

FEandGoingBroke

OK since some of you guys are gonna be sensitive about this, I will edit the entire thing and write it perfectly legibly even though I’m capable of reading it and deciphering it without insulting somebody, from that point throw in your two Cents pretty please.

mountainmanjoe

I actually couldn't care less. Do what you want. I'm just saying the effort you put into your post has an impact on the feedback you'll get. Crapping on people isn't generally a good life strategy. Especially when you want something from them.

FEandGoingBroke

OK the corrections have been made. Now you can read it all with proper pronunciation and spelled English.

what would cause the P3 45 to come back even after being cleared with two new sensors, a new distributor, a new crank sensor, new timing, gears and chain

Could it be he was one tooth off on his cam gear perhaps?

mountainmanjoe

Thank you.
Yeah I would start at the beginning and do things properly. Doing things half-*** means doing them twice or more. (as you just found out).
That means going by the book, and using the alignment marks to get things perfect.
Using a smoke machine to find vacuum leaks.

FEandGoingBroke

I’ve been doing this long enough I don’t need to invest in a smoke machine to find a cam correlation issue. But you DO make a good point.
I am going to do a leak down test on all eight cylinders tomorrow but that has nothing to do with the camp position sensor unless he’s got the cam gear one tooth off but I thought that the car would run like total crap if that was the point when it actually doesn’t.

Also, are you suggesting to tear the front of the motor off and pull the timing cover and verify that the customer did align everything correctly even though the verification process I used verify that everything is spot on within the 16th of an inch anyway, I mean the rotor pointer was not center on the distributor cap pick up but it was definitely touching it relative to its position, and there is a plus or -2° tolerance built into the PCM for that.

I also imagine it could be that he purchased a bad crank sensor and replacing the cam sensor with a new cam sensor when it was a cam sensor failure code could cure the problem because they speak to each other in order to make the proper timing.

I just don’t want to charge this guy for tearing down the front of his motor to verify his work. At this point I can ask questions first to see if anybody’s run across this before.

thank you all for your insight.

mountainmanjoe

obviously. But you said the engine has a manifold vacuum leak (which would explain the surging). A smoke test is more reliable than spraying ether around. At least then you can tick that off the list confidently.

What does the CMP retard show on a scanner?

https://chevroletforum.com/forum/sil...osition-62104/

FEandGoingBroke

I fully understand that he thought there was a vacuum leak. I think there’s a slow correlation between the PCM and the IAC motor which could mean ground it could mean failed chip in the PCM. It could mean the manifold, absolute pressure sensor or the mass airflow sensor, not sending signals fast enough, or the PCM not processing it fast enough to adjust. I did not think there was a vacuum leak I know 100% that there is no vacuum leak in the upper Plenum and there is none in the lower aluminum intake. The motor is still relatively clean even though it does have 124,000 miles on it which is kind of low for a 97 in my experience .

anyhow, I have funds to invest in the smoke machine at the moment, but I am still convinced it is an electrical correlation somehow and yes, the grounds are good and it could be freshly purchased crank sensor. That is bad which I’m going to address tomorrow because I know the business he bought it from and I am an account holder there with privileges above and beyond the average person going into buy something. So I will eliminate the crank sensor tomorrow morning sometime.

it doesn’t run like there’s a vacuum leak that is not the type of surging it’s doing this is a timing correlation surge when I was reading the live stream during a 15 or 2 second second run that I made it was jumping from 17° advanced down to zero when I hit the throttle that shouldn’t happen in my experience with a regular motor but once again, this is a vortex and it’s a Chevrolet and that’s why I came to you guys because the title says Chevrolet forum vortex motors specifically this year through that year and I’m hoping that somebody’s come across this and will tell me that I’m being retarded because I didn’t do XYZ and that will cure the issue. But I’m definitely going to be wires and checking feedback.