92 5.0L idles but stalls when given throttle

[Bamaland601]

hey guy new guy here, 2 days ago i picked up this 92 c1500 has the 5.0L and 5-speed manual transmission.
constantly throwing codes 22 (22 - TPS (throttle position sensor) circuit low (signal voltage low)
& 34 (34 - MAP (manifold absolute pressure) sensor circuit low (high vacuum), nothing else

Parts replaced, Map Sensor, IAC, TPS, EGR solenoid, Fuel relay, fuel pump, new Distributor, Plugs, Wires, Alternator, battery and starter. had the TBI rebuilt with new everything..

some reason i cant clear codes, it will crank and sound excellent idles up to 1500rpm and settles back to 1k-800rpm, once warmed idle slowly bounces from 800 to 1200 rpm

i've taken perfectly working map's and IAC's from another truck and there is no difference.

i can let the truck idle all day it wont die. i can give it a super slow throttle until it reaches 1500-2000 rpm again but any further or too quick it bogs out and dies instantly.

no knocking, ticking while starting or at idle, no smoke, compression good on all 8cyl

im terribly at a loss on what the deal is..

 

[Bamaland601]

i've also tried changing ecm's and it won't even start on the other ecm
just what the heck is going on

 

[ram1220]

Fuel filter?

 

[Fuzzy]

Check the wires going to those sensors and make sure none of them are damaged.

 

[Bamaland601]

thought it to be fuel issues so i dropped the tank this morning to double check everything, well tank was good, filled with gas now.
finding it to be a timing issue, brought the motor to tdc set at 0 degrees reset the distributor to the #1 cyl

now it doesnt start period.. really hoping i wont have to pull everything off just to double check the timing chain

@ram1220 its new and positioned the correct way

@Fuzzy i've traced them as far into the firewall as i could and havent found any knicks or breaks

 

[magimerlin]

How far did you have to reset the distributor? May be 180 out now.... how did you find your tdc... not by just the timing mark right??

sent from what use to be a great country...

 

[Bamaland601]

no i used a piston stop and doing so landed it really at about 1 degree according to the mark but yea im going to double check it tomorrow might be.

 

[Bamaland601]

timing chain had a ton of slack, unfortunately the harmonic balancer pulley i used somehow messed up my threads so now im stuck waiting for a tap set so i won't know if the problem is solved until i can get ahold of one.

 

[Bamaland601]

finally got everything back together, unfortunately its still doing the same thing except it doesnt die as easy. it will not throttle past 2000rpm or it bogs out completely.

tried to set the timing but when i unplug the tan/blk wire to the left of the dizzy the truck starts and dies immediately, if i try to unplug it while running it dies immediately.

still throwing the same codes.

i've already replaced the following: tps, map, timing chain, IAC, fuel pump, fuel pump relay, rear main seal, starter, and distributor.

i was told the TBI was rebuilt at NAPA, now it sprays a nice even cone on both injectors, i dont see any leaks. could it still possibly have a fuel pressure regulator problem even though the fuel pressure never seems to drop even when it goes past 2k rpm and dies.

vacuum lines have all been checked, blown thru and replaced.

i've cleared the ecm dozens of times and they just come right back.


i've tracked all the wires coming from the tps and the map back to the ecm none of them have a problem.

im going to be checking all grounds and pulling and testing the egr valve tomorrow

 

[Brettmd2]

finally got everything back together, unfortunately its still doing the same thing except it doesnt die as easy. it will not throttle past 2000rpm or it bogs out completely.

tried to set the timing but when i unplug the tan/blk wire to the left of the dizzy the truck starts and dies immediately, if i try to unplug it while running it dies immediately.

still throwing the same codes.

i've already replaced the following: tps, map, timing chain, IAC, fuel pump, fuel pump relay, rear main seal, starter, and distributor.

i was told the TBI was rebuilt at NAPA, now it sprays a nice even cone on both injectors, i dont see any leaks. could it still possibly have a fuel pressure regulator problem even though the fuel pressure never seems to drop even when it goes past 2k rpm and dies.

vacuum lines have all been checked, blown thru and replaced.

i've cleared the ecm dozens of times and they just come right back.


i've tracked all the wires coming from the tps and the map back to the ecm none of them have a problem.

im going to be checking all grounds and pulling and testing the egr valve tomorrow

Wondering if you had any luck with your truck? having a similar issue with mine, cant seem to figure it out. thanks