1997 GMC truck issue.

[wtd]

I was able to do the compression test today. Everything looked normal. Here are the results.

#2-190
#4-180
#6-180
#8-180
#1-180
#3-185
#5-180
#7-178

so does the normal compression indicate that there are no mechanical issues or could there still be a bent pushrod?

 

[kc8adu]

just replace with the updated spider.
had several that would miss after high speed runs.
the poppets stick.
the upgrade will also make it run better.
seriously if some kid can kill it revving it to get unstuck with the rev limiter in the pcm it was at deaths door anyway.

 

[wtd]

We are just going to take it somewhere and get it diagnosed. I'm not spending any more of my time on it and I'm not going to take my time to put in a new spider if that is what it needs. I put it all back together and of coarse it still runs like [censored]. The son will be paying for it all.

Wayne

 

[clinebarger]

You can usually get the poppets unstuck buy performing a "REAL" injector cleaning......Involves flowing concentrated Injector Cleaner through the Injectors & Poppets. (AC-Delco X66P for example)

The trick is to remove the CPSFI Assembly & use a Injector Pulse Controller that is capable of pulsing them hundreds of times within seconds.

You can use Paint Pressure Pot to pressurize & regulate the Injector Cleaner to the CPSFI Assembly, Then use a controller to pulse each injector one at a time (I use a OTC 3398)

 

[dishdude]

Originally Posted By: wtd
We are just going to take it somewhere and get it diagnosed. I'm not spending any more of my time on it and I'm not going to take my time to put in a new spider if that is what it needs. I put it all back together and of coarse it still runs like [censored]. The son will be paying for it all.

Wayne


Sounds like a good lesson for the kid.

 

[NYEngineer]

I had a 98 Yukon with that injection system. It started acting strange after a while and I replaced it. It did run nice after that. Not completely sure that's your problem, but it sounds feasible.

When my stepson got his license about ten years ago, we bought him a Mercury Marquis in storybook condition. Car belonged to an old man and had something like 10,000 miles on it. He dug it for about a week until his friends saw it. Then, all he wanted to do was sell it and buy an F150. After a LOT of arguing, my wife finally gave in and let him sell the car and buy a truck. He found an F150 club cab in good condition but it was jacked up on the torsion bars as high as it could go and had huge tires on it. I tried to get him to put somewhat smaller tires on it so we could lower it a little and get the upper ball joints to work properly but there was no talking to him. Anyway, he was showing off in front of all his dodo friends and blew up the transmission. I told my wife NO WAY IN HE!! we were paying to fix that. My friend with a transmission shop fixed it and gave him the price he would charge me, around 1500 dollars. My stepson paid it himself and I have to say, it was a great life lesson because he doesn't abuse cars any more. He currently has a V6 Jeep Grand Cherokee that he takes insanely good care of considering he has zero mechanical ability.

 

[nthach]

One thing I will add on these trucks - I maintain a much more neglected example is the distributors in these are plastic and are known for venting issues. While it may not cause the miss on cylinders 2 & 8, it's worth checking out to see if the cap terminals are corroded - which you did.

The spider is a known troublespot - I say get a can of the strongest carb cleaner you can find and hose down each valve tip while somehow working them. A new Delphi/Delco CSFI spider is almost $400. The truck I maintain is still on the original spider despite the fact it saw nothing but California gas go through it.

 

[wtd]

I did replace the fuel filter today just because it was the original one and installed two bottles of Chevron Techron complete fuel system cleaner in the tank. Years ago GM had a TSB that said this stuff was the only cleaner that worked on this type of injection system. I'm personally not going to be taking off the upper intake to access the tips of the spider. That may be something the mechanic that will be looking at it decides to do. I have already spent more time then I should have on the truck and only did it for my fiance' and not for the son.

I have a 98 Chevy truck with this same motor and fuel injection system with 136,000 original miles and other than one instance when I let the truck sit to long without running it and I think an injector got stuck, I have had no problems with the fuel injection system. I do have an upgraded spider to install in my truck when the time comes. I bought it off of CL new for $100 so I couldn't pass it up even though I don't need it at this time.

Thanks again to everyone who has responded. I will post what the problem ends up being when we get the truck back.

Wayne

 

[wtd]

We got the truck back yesterday from the mechanic and the problem turned out to be the distributor cap which had less than 2,000 miles on it and was a Borg Warner Select cap. The mechanic said it took them quite a while to figure the problem out. Looking at the cap, I still do not see any signs of cracks or anything unusual about it. All I know is that the truck is fixed and runs great again.

The cap that was on it has a lifetime warranty so I'm going to take it back to see about getting a refund or an exchange if they won't do the refund.

Thanks again for all of the suggestions and help.

Wayne

 

[nthach]

The screws on those distributors love to strip as well - the fix that the GMT400 guys recommend is a billet Chinesium dizzy, I got away with the Dorman screw plate. PITA to set the cam/crank correlation, I used a custom PID in Torque Pro to adjust the dizzy mounting position to get rid of the P1345 code.

It's a good idea to stick with an ACDelco OEM part for these. However, I goofed up and I mistakenly ordered the 6-cylinder cap from Amazon. I used a Standard heavy-duty cap from the parts house. No issues... yet.

 

[wtd]

I have the billet distributor in my 98 K3500 with the 7.4L since the screw holes were cracked out and the cap wouldn't stay tight. I bought another one for my 98 K1500 with the 5.7L for when it cracks out as well.

I usually use ACDelco ignition parts on these trucks but the parts store didn't have it in stock so we went with Borg Warner.