dudeinhole

Hi all,

I recently helped a buddy of mine do a headgasket on his 22re pickup (I believe maybe a 93'-94'ish).

We got it all buttoned up and every plug and vacuum line seemed to find its original home.

When trying to start the truck to get it timed, It would not maintain an idle.

When it starts, it would rev up and then die immediately. Each successive start would cause the truck to rev up slightly higher then die. For example, if the first start reved up to 1200 rpms, the second would be 1400-1500, then next 1700-1900 and so on. (These are made up numbers due to lack of tachometer).

We could get the truck to idle very poorly by manually holding the throttle in the engine bay, but it was extremely touchy. When holding the throttle, you had to have it in just the right spot. If you backed off ever so slightly it would die, and if you moved it a hair the other direction, it would rev up to a couple grand be the sounds of it.

We are at a loss as too what could be the issue causing the problem. Hopefully the explanation of the issues is clear enough for you all to paint a picture of what all is going on.

Any ideas or advice would be greatly appreciated!

dudeinhole

bump to the top.

Any ideas anyone?

scope103

"Starts and dies immediately" is the classic sign of a VAF-COR problem (you could even search on that phrase). Make sure the induction plumbing (air cleaner to throttle body, etc.) is all correctly installed. If necessary, jumper B+ to FP to force the fuel pump to run. If that clears up the problem, you've found the source.

But if holding the throttle WILL allow it to run, it's probably not the fuel pump. I would guess timing (if for no other reason than it's so easy to check). You can get timing close just cranking it.

dudeinhole

It has no problem getting fuel to the motor.

when I said we could hold the throttle to get it to run, It idles pretty rough, and is super touchy.

When holding the throttle and trying to time it, rotating the dist. around really didnt seem to change much of anything..

wyoming9

iTrader: (1)

Did you get the Cam gear and timing Chain on correct ??

You have measured the fuel pressure just because the fuel rail has fuel does not mean the pressure is correct .

Terrys87

iTrader: (1)

The only time I ever get a code for the AFM is when the electrical wire is not hooked up. I have seen them bad and not throw a code. Just my experience on that. If you run a resistance check on it per Haynes or the FSM, it usually will tell if it is a good AFM or not. I have had bad AFMs several times.

I suspect a major air leak but you have already eliminated that.

A test that I do and is not in the book but has helped to determine if it is the AFM or some other problem is to simulate the AFM working or not. I remove the air tube connecting the AFM to Throttle Body. You will need to use a screw driver or piece of a yard stick to open the AFM flapper a little to engage the COR, which engages the fuel pump.

Have someone to crank it over while you have the flapper opened enough to engage the pump. Once it is started, I give a little more throttle and then open the flapper some more. Basically trying to simulate or controlling the motor and air flow. It takes a little practice and can give you an idea if you are in the right area or not.

It give you a little more control of what is going on under the hood. If you can get it to respond reasonably well by manipulating the throttle and AFM, it can give you an idea if you are in the right area of the problem or not. Just a little test that I have done and helped in the past.

I have seen the TPS past test and still be bad. There is a thread on here some where to clean the contacts in the TPS and make it pass test. In my opinion, if the truck has a few hundred thousand miles on the odometer, it has millions of cycles on the TPS and should be replaced. I would test it and make sure the TPS is bad before just buying a new one. Did the TPS get removed and not set properly when doing the rebuild?

Intake bolted down good and firm, no air leaks there as well?

dudeinhole

We may have forgot to replace the crush washer the first go around, so while I have not measured the fuel pressure, Im pretty sure its got decent pressure based on the spraying I get..

The tps was not removed, just unplugged and the we plugged it back in on install of everything. does it still need to be reset even if it was just unplugged and plugged back in?

I will test the afm and tps next time I see the truck.

Is it possible for this to just randomly go out? As both were functioning just fine to my knowledge before the head gasket blew.

To my knowledge, all everything is nice and snug and there isnt any noticable air leaks.

The thing that seems strange to me is how sensitive the throttle is, as well as successively reving slightly higher every time we try turning it over.

The truck is in a different city than I, so it may be a few days until We can get some time to go over the afm and the tps.

Any other ideas? Id like to get a decent list of things to go through next time I get down to the truck.

Thank you for the help so far.

Terrys87

iTrader: (1)

If you just unplugged the TPS, it will not need to be adjusted, just so long as you did not remove it from the housing on the Throttle Body.

You do have the throttle cable routed correctly and not binding? For the test above I disconnect the cable from the throttle.

If I get any ideas or others may add them between now and then.

dudeinhole

Too my knowledge, the throttle cable is routed correctly. But stupider things have happened. Ill add it to the list of things to double check.

Im going down tomorrow to meet up with him and tinker with the truck for a bit.

SwVa_1stGen

Like mentioned check fuel pressure first.
RPMs increase from low pressure because of a lean condition

an1176

Have you checked to see if you stabbed the distributor in right? To do so get engine to tdc take the distributor to where the rotor is pointing straight up at 12 o'clock, then stab it. The rotor should rotate back to where it points at number 1.

dudeinhole

Im like 99% sure that the dist. is in correctly. It points to the number 1 plug wire.

an1176

I would recheck it. If you miss it by one tooth it'll look like its pointed at #1 but won't be stabbed correctly and run like crap.