1991 745 Car Wont Start Possible IACV/relay issue

[jimmy57]

If you don't know the voltage from the MAP sensor you haven't checked the primary thing that makes that fuel system deliver the correct amount of fuel.

[745volvowagon]

Yes but would that be throwing a missing signal from the iacv, or a closed iacv valve?

the 2-2-1 could be possibly from the exhaust manifold gasket it looked as if it were never replaced and they were worn and i could see where there could possibly have been leaks. so maybe air was escaping and causing the o2 sensor seeing different ammount of air or something causing a rich or lean most likly a lean situation, the o2 sensot has about 15k on it if that it has been replaced within the last 1.5 years i believe they say to replace the o2 sensor like 70k miles. if its bad i would be suprised.

[745volvowagon]

ok. update

i started to put 1 and 2 together.

when i turn the key the odometer blips up, and a couple of weeks ago the car would while going at any speed at at 50MPH.

i pulled the CPS and it had what looked to have collected metal and the metal piece looks rusted.

i cleaned it off and reinstalled it.

the car finally was trying to start however would not idle.

can this be the CPS failing? it looks newer however it seems to be presenting failing issues

[745volvowagon]

Ok so I got my hands on a miltimeter today

I checked the voltage at the sensor I got 4.99 volts that w as as test the ground and signal wire.

I tested the ground from the pin at the connector and the positive terminal I got 12.44 volts

I plugged the tps in and I inserted the red into the signal and the back into the ground.

I got lIke .045v closed throttle and 4.99 volts immediately once the throttle clicked no graduation of voltage it just went straight to 5 volts so I think the tps is toasted.

Who else thinks so?

I replaced the cps today the car now is
starting however I believe bad idle is the main problem.

Can the tps throw the iacv code? Since the tps isn't showing correct voltages and possibly not working at all when it clicks it's not showing the iacv any volts or the tps isn't showing any volts causing the iacv to not receive a signal?

It's typical now looking at it the throttle is idling at like 300 rpms the car won't Rev up and if it doesn't it seems like it hits a wall and just keeps revving over and over gain but won't go past that Rev point no matter how much throttle is introduced

[jimmy57]

That isn't a TPS. IT is a throttle switch with closed throttle and WOT contacts.
Check all three wires at MAP. One is ground, one is 5V reference or supply and one is the signal. Signal would be 4.4V range key on eng off and 1 volt range idling.

Low fuel pressure will let it idle poorly and not rev up. Regina cars are notorious for fuel pump failure.
No easy fuel pressure test port on that one but if you remove the rubber return line off the fuel press regulator on fuel rail and substitute a hose with a gauge in it to deadhead the system it should go 70 psi range.

[745volvowagon]

''That isn't a TPS. IT is a throttle switch with closed throttle and WOT contacts.
Check all three wires at MAP. One is ground, one is 5V reference or supply and one is the signal. Signal would be 4.4V range key on eng off and 1 volt range idling.

Low fuel pressure will let it idle poorly and not rev up. Regina cars are notorious for fuel pump failure.
No easy fuel pressure test port on that one but if you remove the rubber return line off the fuel press regulator on fuel rail and substitute a hose with a gauge in it to deadhead the system it should go 70 psi range.''

checked map sensor

Signal Wire Got 4.7 Volts Key on Eng of
Reference Wire Got 5.5V
And the other Wire Got A 0.01V

With the car idle best it could i got 1.3V

The fuel pump is new, so is the Fuel Filter along with the fuel injector o rings and fuel pressure regulator o rings

When I try to drive the car I can push the throttle to the floor the car will barely go. It backfire and pops you cannot get it to go above 25mph if that.

So you are saying the tps is only a switch and it shouldn't graduate in voltages? With it plugged in or not the car acts the same

[745volvowagon]

I checked the Harness to the IACV and i was getting 12Volts now i know once the TPS or throttle Switch Clicks it shuts the 12 Volts off from the IACV.... With the probes in reading 12v i turned the throttle and heard the click and still no shutting off of the IACV.

I dont have a pump so i dont know what the reading is for every 5 inches of air if the MAP is dropping 1volt or not.

thus far i got the signal wire to reads properly, the reference wire reads properly, and the ground wire reads properly. but still dont know how vacuum effects the voltage reading.

i mean this car will barely idle, i can give it gas and nothing happens it or it tries torev but doesnt.

ive replaced:

Fuel pump
Fuel filter
Fuel injector O rings
Fuel pressure regulator O rings
Distributor Cap
Rotor Button
Spark plugs twice
Crankshaft positioning sensor
Intake manifold gasket
Exhaust Manifold gasket
throttle body gasket

Checked all fuses
#1 is good
#11 is good
Checked Fuel Pump relay x2
Checked Radio Supression Relay

come on someone guide me in a place that might help me get this running this is my only car so walking has been what i have been doing. i am begging you guys someone give me a idea of what to do i have checked and replaced ALOT of stuff only to come up empty handed. please