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LMC Truck



Username Post: 88 S-I0 4.3 HAS SPARK WON'T START        (Topic#347912)
chevylover 
Member
Posts: 97

Reg: 05-25-04
10-27-17 11:36 PM - Post#2712428    

I PUT LOTS OF DIST. PARTS IMPROVED SPARK. BEFORE DOING ALL THIS I PUT FURL DOWN THE TBI AND IT FIRED. AFTER ALL THESE PARTS THE ENGINE WILL NOT FIRE AND TURNOVER. DO YOU HAVE ANY IDEAS? CK. FUEL PUMP IT'S FINE I CAN HEAR IT RUN. ANY IDEAS WILL BE TRIED. THANKS



 
LMC Trucks
gchemist 
Senior Chevytalk Moderator
Posts: 24202
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
10-28-17 04:36 AM - Post#2712435    
    In response to chevylover

If the fuel pump primes and it starts with fuel down the TBI, fuel pressure may not high enough. First, with the key on, check for power at the fuel injectors. Second, ohm check the pickup coil. The pick coil is used by the ECM to fire fuel injectors. The pick up coil should read 500-1500 ohms. If it reads outside that range, it’s bad. The entire distributor has to come out to replace it. I just did an 87 TBI truck. We ended up replacing the entire distributor. You need a special adaptor to test fuel pressure.

Does it have any codes? Email me. I’ll send you a TBI troubleshooting guide.

'95 Jimmy SLT (Bought @131,814)
'83 Silverardo XST - ZZ4 powered
'96 GMC Jimmy LS Ret. @236651 miles


 
chevylover 
Member
Posts: 97

Reg: 05-25-04
10-28-17 07:23 AM - Post#2712452    
    In response to gchemist

HI, THE TRUCK RAN FOR A FEW MOMENTS BEFORE I CHANGED ALL THOSE PARTS. AFTER THE PARTS THE MOTOR NEVER STARTED EVEN WHEN I PUT FUEL IN TBI.



 
gchemist 
Senior Chevytalk Moderator
Posts: 24202
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
10-28-17 11:56 AM - Post#2712471    
    In response to chevylover

Are all the connections tight? So was the distributor was taken out? Are all the fuses ok?

'95 Jimmy SLT (Bought @131,814)
'83 Silverardo XST - ZZ4 powered
'96 GMC Jimmy LS Ret. @236651 miles


 
chevylover 
Member
Posts: 97

Reg: 05-25-04
10-28-17 01:29 PM - Post#2712478    
    In response to gchemist

YES EVERYTHING IS TIGHT.



 
gchemist 
Senior Chevytalk Moderator
Posts: 24202
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
10-29-17 03:15 AM - Post#2712525    
    In response to chevylover

Please email me. I'll send you a PDF troubleshooting guide. It will guide step by step on things to check. You'll need a digital voltmeter.

Does it spark? You'll have to test for power at certain points per the PDF guide. My email is under my profile.

PDF file sent. Good luck! Let us know what you find. Post questions too.

'95 Jimmy SLT (Bought @131,814)
'83 Silverardo XST - ZZ4 powered
'96 GMC Jimmy LS Ret. @236651 miles


Edited by gchemist on 10-30-17 04:16 AM. Reason for edit: No reason given.

 
chevylover 
Member
Posts: 97

Reg: 05-25-04
11-08-17 02:20 PM - Post#2713686    
    In response to gchemist

HI, I HAVE A FEW QUESTIONS. I HAVE GOOD SPARK. NO FUEL ON PLUGS EVEN IF I PUT FUEL IN TBI ? DIDN'T CKECK THE FUEL LINE PRESSURE YET. WILL IT CAUSE NO FUEL IN TBI IF LOW ? I CHECKED THE INJECTORS WITH A LITE AND THEY ARE WORKING BUT STILL NO FUEL. NO PLACE IN TBI AND ON PLUGS. COULD IT BE THE COMPUTER ? ANY INPUT WILL BE HELPFUL. THANKS WALT



 
Shepherd 
Frequent Contributor
Posts: 1042

Loc: Lake George, NY
Reg: 11-11-15
11-08-17 03:14 PM - Post#2713694    
    In response to chevylover

How did you check the injectors, noid lite?



 
chevylover 
Member
Posts: 97

Reg: 05-25-04
11-08-17 07:55 PM - Post#2713728    
    In response to Shepherd

Lite with two probes and lite on top.



 
Shepherd 
Frequent Contributor
Posts: 1042

Loc: Lake George, NY
Reg: 11-11-15
11-09-17 07:16 AM - Post#2713752    
    In response to chevylover

If the injector has 12v to it, ok, the ecu pulses to ground on the other side, so hooked up correctly the lite should flash as the engine cranks.



 
gchemist 
Senior Chevytalk Moderator
Posts: 24202
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
11-09-17 07:50 AM - Post#2713759    
    In response to Shepherd

Does the fuel pump still prime for 2 seconds? Verify fuel pressure. Even if the pump primes, fuel pressure can be too low. You can disconnect at the past the filter or TBI.

'95 Jimmy SLT (Bought @131,814)
'83 Silverardo XST - ZZ4 powered
'96 GMC Jimmy LS Ret. @236651 miles


 
2blu52 
"17th Year" Silver Supporting Member
Posts: 18216
2blu52
Age: 84
Loc: Montana
Reg: 03-12-02
11-09-17 07:51 AM - Post#2713760    
    In response to chevylover

If you got air, and spark then you have no fuel! So identify what is happening with that part of the system.

"PEACE IS THAT GLORIUS MOMENT IN HISTORY WHEN EVERY ONE STANDS AROUND RELOADING"

THOMAS JEFFERSON


 
CowboyTrukr 
"6th Year" Silver Supporting Member
Posts: 3821
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
11-11-17 01:09 PM - Post#2714038    
    In response to chevylover

Walt, it’s not the computer. Resist the temptation to replace it.

As mentioned, check your fuel pressure. You need a TBI pressure adapter. Check right after the fuel filter or right at the back of the throttle body. I bought an adapter and a 15psi gauge that stays in place on mine.

Gchemist’s troubleshooting guide is a good thing to have.



Attachment: 2348FC52-C00B-48D0-BDC9-7C7253D903FC.jpeg (465.85 KB) 10 View(s)




Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD

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


 
LMC Trucks
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