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Username Post: Starting issues        (Topic#363213)
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 05:07 AM - Post#2807319    

So I have this new infuriating issue with my truck im hoping other people could shed some light on.

Lately it seems to have developed almost like a vaccum leak of some sorts. At idle its fine. Give it fuel to ~1,300rpm it starts to misfire/ spudder like crazy with an RPM drop. On top of that. Shut it off (only while the engine is hot) it doesn't want to start. It just cranks acting like it doesn't get any spark. Except if you go about half throttle then it seems to start. (Not sure if that was just a coincidence or not, only tried it once so far)

I pulled plugs to verify gap is correct after adjusting it from .045 to .035 it still has the same issue. All plugs looked good.

Things that have been replaced within the last 1,000 miles

All vaccum lines
EGR valve
Spark plug wires (unrelated reason)
Knock sensor and plug for it
Air filter
Fuel filter
IGN Control module (had the new one tested to confirm it works)


Info about vehicle
94 chevy K1500 with an '88 350 in it pulled from a GMC C1500
163,xxx miles on body
The engine is "a jasper rebuild with 87,xxx miles"

Any help is greatly appreciated!!



 
Shepherd 
Frequent Contributor
Posts: 2195

Loc: Lake George, NY
Reg: 11-11-15
11-09-20 06:37 AM - Post#2807328    
    In response to Sixfootman3

Welcome to CT. Is this throttle body injected?



 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 06:40 AM - Post#2807329    
    In response to Shepherd

Yes it is tbi

And thank you for the welcome



Edited by Sixfootman3 on 11-09-20 06:41 AM. Reason for edit: No reason given.

 
Silverado Kid 
Newbie
Posts: 38

Age: 72
Loc: Jackson California
Reg: 07-26-16
11-09-20 09:13 AM - Post#2807340    
    In response to Sixfootman3

Did you replace all these parts before you had the problem or were you trying to fix the problem and then started replacing them? Sounds like a fuel problem if it starts when you push the gas pedal and then starts. Fuel pump? Injectors? Fuel filter? I would check the fuel pump pressure first and go from there. Could be your fuel pump is giving up the ghost but that is only one of several possibilities.



 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 10:32 AM - Post#2807345    
    In response to Silverado Kid

Aside from the spark plug wires and air filter. Yes the problem occurred first, and then I started fixing the rest of it. However I had some check engine codes that I was repairing. Hence the EGR replacement and Knock sensor. Ive had a check engine code for the longest time regarding the coolant temp sensor, however the truck has drove 20K miles like that with not a single issue. But I did not notice the egr or knock sensor codes until after I checked them for this weird problem.



 
CowboyTrukr 
"10th Year" Silver Supporting Member
Posts: 4506
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
11-09-20 10:50 AM - Post#2807348    
    In response to Sixfootman3

Sorry about the parts roulette game. Have you checked your fuel pressure?

Greg

‘01 Silverado 2500HD 8.1/Allison 1000 Xcab/LB
'00 Explorer XLT 4.0 SOHC V6 Auto
'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500 SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 11:31 AM - Post#2807352    
    In response to CowboyTrukr

I have not. Im not opposed to it. But totally honest here unsure how to, nor do I own a fuel pressure gauge

This has pretty much been a parts guessing game. On the bright side, I work at autozone so I get a 20% discount so there's a small glimmer of light in all this.

I've honestly skipped doing that, because I figured If it drives fine it wouldn't be that.


Now to add to this issue(s). When I just started it. And put it in reverse. The engines rpm dropped so bad it shut off. It did that once. When I started it up after that, it didn't do it a second time. The rpm naturally dropped but it caught itself




 
Shepherd 
Frequent Contributor
Posts: 2195

Loc: Lake George, NY
Reg: 11-11-15
11-09-20 11:57 AM - Post#2807354    
    In response to Sixfootman3

It is possible some of control algorithms in the ecu are skewed because of the engine change, just a guess. 6 year difference could be an issue.



 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 12:17 PM - Post#2807355    
    In response to Shepherd

I did think about that. But I've put at least 15k miles on this engine without an issue before..



 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 12:27 PM - Post#2807356    
    In response to Sixfootman3

Does anyone think it could be the pick up coil in the distributor? I'm focusing more on the issue of when the engine is hot, it does not start, just cranks...

The Haynes manual says that could be an issue in the troubleshooting section for no warm starts. But, anyway this could tie over into the weird idle?



 
someotherguy 
Senior Moderator
Posts: 29310
someotherguy
Loc: Texas
Reg: 08-01-03
11-09-20 12:54 PM - Post#2807359    
    In response to Sixfootman3

I would have addressed the CTS a long time ago if you've had a code for it. They usually go bad slowly without ever setting a code before you notice problems. You can check the CTS itself with an ohmmeter (info linked in the FAQ post at the top of this forum) before replacing, as you may have other issues such as grounds near the thermostat housing. They need to be in top shape.

Fuel pressure is easy enough to check with the correct gauge kit. Info also linked in the FAQ.

Checking the pickup coil with an ohmmeter...you guessed it...linked in the FAQ.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 01:17 PM - Post#2807360    
    In response to someotherguy

That ECT sensor is in itself deserving of another separate post. I have two new sensors, (the one on the drivers side of the block, and the one at the inlet) and it still does not work correctly and never has since this swap.. although the temp sensors part number are the same for the 88 and 94, same connectors too. The wiring looks good on them traced them as far as I could.

I will test that coil right now and get back




 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-09-20 01:48 PM - Post#2807361    
    In response to Sixfootman3

Pick up coil reads 956ohms



 
Sabino 
Member
Posts: 149

Reg: 07-16-05
11-10-20 07:43 AM - Post#2807399    
    In response to Sixfootman3

X2 on checking fuel pressure. Marginal fuel pressure can cause these sorts of problems.

65 Belair 350
68 Camaro 327
93 Suburban 5.7L TBI


 
Sixfootman3 
Newbie
Posts: 9

Loc: Hershey PA
Reg: 11-09-20
11-10-20 05:58 PM - Post#2807423    
    In response to Sixfootman3

UPDATE!!

After countless hours going over everything, and $$$ down the drain playing part roulette. It seems one of the coolant temp sensors went bad. Ive always assumed something went wrong in that circuit since the temp gauge has never worked since this swap, and I've had code 15 for the longest time. But after I replaced the one on the inlet. *knock on wood* seems to be running fine. And all the codes dissappeard, Minus the fact when I drive for ~30 minutes, I have a check engine light apear. But when its shut off and turned back on the code dissappear.

I am going to assume now that it is still the code 15 (low temp indicated) since the thermostat seems to be junk. After installing an aftermarket gauge, it runs ~140 or so.

Tomorrow I will be installing a 195° 'stat in it.

Thank you for everyone and their contributions to this nightmare



 
jcSS63 
Newbie
Posts: 3

Age: 64
Loc: Medina, Ohio
Reg: 07-08-17
11-21-20 11:34 AM - Post#2808260    
    In response to Sixfootman3

Sounds like it might be a fuel delivery problem. I would check fuel pressure @pressure shrader. Some of the TBI you had to get to the fuel line driver’s side on the frame. It was close to front fender tire well. Block return line. Hope it helps



 
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