Main IndexAuto Repair Home Search Posts SEARCH
POSTS
Who's Online WHO'S
ONLINE
Log in LOG
IN









Search Auto Parts

88 GMC S15 2.5L TBI won't start after replacing head gasket


  Email This Post



bigelow
Novice

Jul 17, 2012, 12:39 PM

Post #1 of 11 (3981 views)
88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Just replaced a blown head gasket in my 88 GMC S15. It's a 2.5L TBI engine. Got everything back together. As far as I can tell I got all of the wiring reconnected. Engine cranks but will not fire. Truck started fine before I tore it down. When I look into the throttle body and move the accelerator cable I do not see any gas squirting into it. However, I don't really know anything about throttle body's so I don't know if they do that like carburators do. Any suggestions would be greatly appreciated.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 17, 2012, 12:52 PM

Post #2 of 11 (3963 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

No, you wont see fuel squirt just looking down throttle body like a carb. Ran before and not now so look for anything disturbed or wrong with the job at a glance and then the basics of fuel pressure, pulse to injectors, spark with a tester and if that shows fine compression if you somehow have this way off by valve timing,

T



bigelow
Novice

Jul 17, 2012, 1:01 PM

Post #3 of 11 (3957 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Thanks for the reply, Tom. Can you elaborate on what you mean in regards to checking pulse to injectors? I'm an old carburator guy. Haven't moved up to the injector world, yet. Frown

Thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 17, 2012, 2:23 PM

Post #4 of 11 (3923 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Noid light is a special and relatively cheap tool to check pulse for injectors. That or just spray some starting fluid or carb cleaner down throttle body if you know there's spark and if it fires up for a second or two then you know it's a fuel problem to chase and can pretty much forget spark problems,

T



bigelow
Novice

Jul 17, 2012, 2:34 PM

Post #5 of 11 (3919 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Ok, thanks!


re-tired
Veteran / Moderator
re-tired profile image

Jul 17, 2012, 6:48 PM

Post #6 of 11 (3892 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

If it turns out you have inj pulse and spark at the end of the plug wires, make sure you have fuel pressure. All this stuff checks out , did you have the head resurfaced ? Did you adjust the vaves properly?


LIFE'S SHORT GO FISH


bigelow
Novice

Jul 17, 2012, 7:10 PM

Post #7 of 11 (3886 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

At this point there is no spark at the coil or the plugs. Unfortunately, I ran out of daylight and had to stop for the night. Will start back on it in the morning and try to determine why.


bigelow
Novice

Jul 18, 2012, 8:22 AM

Post #8 of 11 (3858 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Any recommendation on what to check first to try and determine why there is no spark?

Thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 18, 2012, 9:56 AM

Post #9 of 11 (3847 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Spark before and none now? Back. Check all electrical connections you removed to do this and fuses everywhere that should have power. If oil pressure switch* was disturbed or any wires pinched.

*Note sure on that but some can shut spark down.

?? Does distributor rotor turn? Shouldn't have been involved. Not much help but something in the process caused no spark if there before,

T



bigelow
Novice

Jul 18, 2012, 2:55 PM

Post #10 of 11 (3825 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

All wiring appears to be connected properly. All ground wires are connected. Checked fuses. All seem fine.

I pulled the ignition coil off and used my Actron Autoanalyzer to test it per instructions out of a Chilton manual. I did not get any readings. So, I decided to go and get a new one. Prior to putting it on, I did the same test on the new one. No readings on it, either. I'm guessing I'm not doing the test properly. Does the coil have to be on the engine to test it? Since it's up underneath the intake manifold I took it off to test so that I could get to the connectors. If it has to be on the engine to test it, I'll reinstall it and try to test it that way.


bigelow
Novice

Jul 19, 2012, 9:35 AM

Post #11 of 11 (3777 views)
Re: 88 GMC S15 2.5L TBI won't start after replacing head gasket Sign In

Update

  • Tested the pick up coil in the distributor. It tested good.
  • Ignition coil tested good.
  • Getting approx. 11.9 volts to the ignition coil from the ignition switch.

Still no spark.






  Email This Post
 
 


Feed Button




Search for (options) Privacy Sitemap