So i bought a 51 Whilly

[Hip]

Before you get too far into it you may want to see if the TPS is working correctly. With the volt meter hooked up work the throttle by hand (key on engine off) slowly and watch the voltage. It should move steadily in progression without any jumps up or down. You're looking for dead spots where the voltage has a dead spot or spike....Could be bad at idle.

too late i had already ****ed with that screw....

so yes i have a gauge on the fuel rail test fitting the entire time for troubleshooting, steady 60 psi. i now have a vacuum gauge also. vacuum runs steady during startup 17In for the thirty seconds then jumps down with the loping to like ten and moves up and down.


so i dont have the EGR wired into the system but the EGR is still bolted in place. im assuming the valve just stays closed. do i need to do something there?

 

[Hip]

Hell I was just going to bump this thread since I have mine in the shop right now too.

Throttle Position (TP) Sensor

ADJUSTMENT & TESTING


The TP sensor wiring should consist of a 3-wire harness connector. The gray wire is normally the 5 volt reference signal from the computer control module. The dark blue wire should be the TP signal and the black wire is ground.

Because the TP sensor on these engines is bolted into a fixed position, no adjustment is necessary or possible. If the sensor does not give proper readings (and other problems with the circuit are not to blame), the faulty TP sensor must be replaced.

1. If available, connect a scan tool to the ALDL/DLC. If a scan tool is not available, use a digital voltmeter to backprobe the TP sensor connector terminals for the ground (black wire on end of connector) and sensor signal (dark blue wire usually at center of connector). By backprobing the connector, a voltage reading can be taken without disconnecting the circuit and without piercing the wires.
2. Turn the ignition ON, but do not start the engine. Check the voltmeter or scan tool for TP sensor output. Voltage should be 1.25 volts or less with the throttle closed. Open the throttle and watch for a smooth change as the voltage increases. Voltage may go as high as 4.5 volts at wide open throttle. If voltage with the throttle closed is greater than 1.25 volts, or if the voltage does not increase smoothly as the throttle is opened, replace the sensor.

test sat, start throttle closed .485 V which is less than 1.25 V

smoothly increases up to 4.5 volts as you open throttle. :awesomework:

 

[ain'tstuckjustresting]

Mine's .649v-4.51v

my ECT reads 1.35 k ohms @ 96deg.

 

[Hip]

Mine's .649v-4.51v

my ECT reads 1.35 k ohms @ 96deg.

WTF is that?

 

[wilbilt]

WTF is that?

engine coolant temp

 

[wilbilt]

Mine's .649v-4.51v

my ECT reads 1.35 k ohms @ 96deg.

is that within spec?

 

[ain'tstuckjustresting]

I guess, it says like 10k ohms @ -40deg to 4 ohms at 266deg is spec. I heated up the one out of that spare tbi manifold and it was really close at that temp. I guess it's ok.

 

[Hip]

Mine's .649v-4.51v

my ECT reads 1.35 k ohms @ 96deg.

so yours is doing the same thing ehhh.

after this weekend my suburban started doing it, its a freaking epidemic:redneck: grab your women and kids....:haha:

no laughing matter to me anymore i picked a good running motor so i would have no issues now im having nothing but issues.:kissmyass:

 

[Binder]

May I ask what isn't stock about the setup?...What's been modified?

 

[Hip]

May I ask what isn't stock about the setup?...What's been modified?

removed the catalyic converter and EGR, evaporative canister.

had a harness and ECU done by http://www.fuelinjection.com/portinj.html

i think im gonna give em a call today.

motor is stock.

 

[Hip]

just got off the phone with the injector specialties and they told me to unplug the PROM they made for me and try it and see what happens?

 

[ain'tstuckjustresting]

It'll run w/ no prom?

I've been wondering about my custom chip too. Motor is completely rebuilt and was a good runner out of a blazer. Mine has a Howell harness but all the sensors/egr are hooked up. I cleared all the codes and ran mine for 1/2hr w/ the idle kicked up so it wouldn't die. No codes set now but still won't idle correctly. Plugs are wet and exh smells super rich.

It's frustrating when you need to get the motor running good so you can focus on all the other little projects.

 

[zukkev]

just got off the phone with the injector specialties and they told me to unplug the PROM they made for me and try it and see what happens?

Is their PROm a piggy-back style, or does theirs replace the one inside the puter?

 

[Hip]

It'll run w/ no prom?

I've been wondering about my custom chip too. Motor is completely rebuilt and was a good runner out of a blazer. Mine has a Howell harness but all the sensors/egr are hooked up. I cleared all the codes and ran mine for 1/2hr w/ the idle kicked up so it wouldn't die. No codes set now but still won't idle correctly. Plugs are wet and exh smells super rich.

It's frustrating when you need to get the motor running good so you can focus on all the other little projects.

your issue sounds like a leaky injector or CPI spider?

Have you popped off the upper intake and looked for clean spots or puddled gas?

other little projects, my air compresser pulley (i made myself) needs one more groove as it keeps wanting to jump off the pulley.:fawkdancesmiley:

Is their PROm a piggy-back style, or does theirs replace the one inside the puter?

YEs its a piggy back it plugs into where the old prom goes and the old prom plugs into the side of it so it is effectively between the existing prom and ECU.

when piggy back chip is unplugged and old prom plugged in it starts fine but does not run well at all. it appears to idle without loping but vacuum is low and it wont accelerate, however it does cycle to a point where it has decent vacuum, everything kinda smooths out, you can rev it up and then goes back into low vacuum. timing of above cycle seems random...

in about an hour ill call the company back and see what they say.

i didnt get a chance to look at timing marks or anything.

 

[zukkev]

If the vacuum's low, could it be the timing? Did you disconnect the timing connector when you set it?:corn: Should be a small tan wire with black tracer....the plug is tiny...:redneck:

 

[Hip]

If the vacuum's low, could it be the timing? Did you disconnect the timing connector when you set it?:corn: Should be a small tan wire with black tracer....the plug is tiny...:redneck:

yes sometimes they are hard to find i put mine right next to the battery.

base timing set at 0 Deg. cause you gotta reset the ECU after setting the base timing....

timing and vacuum are very related it appears. as timing mark moves around so does vacuum. im thinking whatever controls the timing after cloosed loop is probably the culprit.

what does that the Dist module and ECU together?

 

[Hip]

so for further troubleshooting i need a scanner tool.

i am supposed to run it like a 93 S-10 blazer using an OE scanner...

anyone have one and be willing to run this thing for me?

never mind a bubby at work has one with a bunch of OE adapters....

ok time to fix my ac pully.....

 

[Binder]

yes sometimes they are hard to find i put mine right next to the battery.

base timing set at 0 Deg. cause you gotta reset the ECU after setting the base timing....

timing and vacuum are very related it appears. as timing mark moves around so does vacuum. im thinking whatever controls the timing after cloosed loop is probably the culprit.

what does that the Dist module and ECU together?

In a nutshell it's a table that is programmed into the PCM. The table is based on RPM and vacuum so as the RPM fluctuates (so does vacuum) the timing value will change back and fourth...All this leads to a surging condition. Programming is probably going to be required to fix it.:booo:
Before messing with the programming though you need to make sure all other perameters are good. Did you set the IAC back to spec? It's important that both IAC and TPS are good at idle.

 

[Hip]

so it appears that the piggy back chip does is eliminate the codes for the Smog equipment i dont have. the vehicle will run just fine with or without it.

The person at the ECU Harness place asked me to scan it and tell them the results.


rick i adjusted the idle control screw back to where it was as best i can tell.

basically that what the ECU place said is to eliminate all mechanical things first and they consider sensers to be mechanical things....

 

[Hip]

so i got a scan tool that does OBD II and will also do OBD I....i ran the scan and i think i found my problem, my map senser has three wires to it purple - ltgreen - grey.

it shows 4.99V at idle and should show very little at idle and 4.99 at WOT.

i look at all the diagrams and the wires should be
ltgreen - purple - grey....purple wire should be in the middle i believe the reference voltage and enable voltage wires are swapped at the connecter.





ill call the wiring place again tomorrow they have been very helpful on the phone.