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Tbi Update!!!

southernspeed

southernspeed

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UPDATE. ...Thoughts?
I've just checked the fuel filter...clean as a whistle.
My crappy Summit fuel guage in-line just before the throttle body was reading 11 psi until i reved it up and it dropped to 3psi. Not trusting it I put a Snap On gauge on it and it reads 12 all the time idle or 5000rpm. When hot after 5 mins of hard driving it still read 12psi but was 'fluttering' a bit but still constant. I gave it quite a hard drive and all seems well! Which is a PIA as I haven't done anything so it could come back at any time :mad: .
So was I just unlucky and the FPR stuck for a bit? TPS or MAP had a mad moment? I wouldn't have thought they have 'off' moments....thought that was just women!! :rolleyes:
Any thoughts gratefully recieved!

The '90 tbi motor in my '78 has just starting acting like it's getting real bad fuel starvasion. I just had to drive it home on a very light throttle and low revs. Try to open it up a bit and it just dies and bogs down, sounds like the motor actually cuts for a moment. As soon as the revs drop it picks up again. No popping or banging so it seems very fuel related rather than electical.
Too busy at work to look right now but I'll check the fuel filter and lines as soon as poss but has anyone else had this or can suggest other sensors that might make it do this?
Everything is new inc. in-line pump, filter, hoses and a rebuilt TB unit.
Maybe my tank is just so rotten inside it's fouled up the new filter already!!
Any suggestions? Thanks.
 
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Sounds like similar problems that a friend of mine was having with his 97 Tahoe. Ended up being a fuel pump. Actually he is on his 3rd new pump! The last time he thoroughly cleaned out his tank and found a ton of junk in the bottom. Even plastic shavings from when the tank was made!

His truck ran great from idle to about 2k rpm. Then it had no power and wanted to die until he let off.
 
I had that happen once from a crap tank of gas. Truck wouldn't even keep up with traffic on the highway. I was on a long road trip, so I just stopped and swapped in a new fuel filter, but no help. When it got down to about 1/3 of a tank I filled up again and the problem was gone within half a mile. :doah:

Don't throw an expensive fuel pump at it unless you're sure that's the problem... :cool1:
 
SierraClassic said:
I'd also say fuel pump :)

They can be a real pain in the butt!
Click to expand...

ditto, sounds EXACTLY like what mine did when the pump died, kept throwing false codes too,,,really sucked, i drove it home from San Diego,CA to Phoenix like that. :crazy:
 
My car did this but it was the spark plugs and wires. I thought it was gas, but just wires and plugs
 
OK thanks guys. I'm kinda leaning toward a fuel delivery problem of some sort. It's a Turbo City external pump with an aluminum bodied filter inline just before it. I'll check out the filter first. Not sure how I can check the pump really as checking FP at the TB unit could indicate a bad FPR if it's low. The FPR is a new Jet adjustable one so that should be ok anyway, mind you, the pump and filter are new so hopefully it'll be a clogged filter. I'll check it out this weekend if I can get some of this work cleared out before I go on holiday! :doah:
 
If the filter dosn't fix it. Check the TPS. It could have gone bad. Check for trouble codes. Do you have a scanner?
 
Thunder said:
If the filter dosn't fix it. Check the TPS. It could have gone bad. Check for trouble codes. Do you have a scanner?
Click to expand...
I've got Winaldl and EFIlive so I can use those. It didn't throw any codes at the time but I haven't put a scanner on it yet. TPS...good idea, thanks.
 
UPDATE. ...Thoughts?
I've just checked the fuel filter...clean as a whistle.
My crappy Summit fuel guage in-line just before the throttle body was reading 11 psi until i reved it up and it dropped to 3psi. Not trusting it I put a Snap On gauge on it and it reads 12 all the time idle or 5000rpm. When hot after 5 mins of hard driving it still read 12psi but was 'fluttering' a bit but still constant. I gave it quite a hard drive and all seems well! Which is a PIA as I haven't done anything so it could come back at any time :mad: .
So was I just unlucky and the FPR stuck for a bit? TPS or MAP had a mad moment? I wouldn't have thought they have 'off' moments....thought that was just women!! :rolleyes:
Any thoughts gratefully recieved!
 
I was thinking that too but it would seem unusual. There's not much to stick really. It's all new and the fuel filter was clean so no dirt could have gotten thru there. Odd. Can't think of anything else though. I've been considering getting a vaccum ref FPR (just surfing for one now) so I may change it anyway. I'm going away for a week in my '91 so hopefully I can get one ordered and it'll be here for when I return (as long as I can find someone who sells overseas! GMPartsdirect have them but won't ship overseas or take my c/card!)
 
mouse said:
Any possibility of fuel starvation from low fuel level in an un-baffeled tank?
Click to expand...
LOL....no, I put £90 worth of gas in shortly before it went really bad, but it did it a bit before I put the gas in.
 
blazerguy 90 said:
It could be the coolant temperature sensor, that would cause the problems your having.
Click to expand...
Checked that, it's fine thanks.
 
do you have enough chip for the cam. I put i TBI setup on my friends blazer which had a bigger stock cam and it would pop and cut out like crazy
 
1979jimmy350 said:
do you have enough chip for the cam. I put i TBI setup on my friends blazer which had a bigger stock cam and it would pop and cut out like crazy
Click to expand...
I've got about 450 miles on this set up now and it's been fine. And it's fine again now. It shift so hard at 5000rpm I'm worried I'm going to break something!!! No, this is some kind of fuel delivery glitch.
 
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