88 4L Renix cranking issue

[DaveVmax]

ok wired it....

with a brand new relay and the pump doesnt come on...

could it be that resistor? can i bypass it to check?

 

[DaveVmax]

nevermind i bypassed the resistor and it still doesnt work

 

[DaveVmax]

just replaced all the relays and still nothing

 

[DaveVmax]

ok turns out it was a bad wire further down on the ballast resistor so it works now.


now im going to check the battery and replace the HOT wire cable

 

[cruiser54]

Cool beans. Glad you got it figured out.

 

[DaveVmax]

ok bringing this up again...

still cant figure out this starting issue.

so far everything ive changed...

-all the main grounds plus a new ground from battery to body
-starter relay
-all "hot" main cables
-plugs
-wires
-cap/rotor
-coil
-TPS
-IAC
-starter
-ICM
-CPS
-injector seals
-cleaned the injectors
-check valve went bad so i replaced with in line check valve


just wanted to add that when the truck starts it runs perfect.

 

[Ecomike]

Did you ever test the cranking voltage of the CPS?

I had to move my closer to the flex plate. I also had to replace the brand new one ( Scrapped the Autozone one for one from Rockauto), as it seems it had an iffy internal connection, worked one minute, then not the next. It was also a random no start issue. Once it started it worked fine.

 

[cruiser54]

Mike offers good advice here. Even if he stole it from me............LOL

 

[Ecomike]

Mike offers good advice here. Even if he stole it from me............LOL

Stole it? I thought it was on loan?

:laugh:

 

[cruiser54]

Stole it? I thought it was on loan?

:laugh:

You're always welcome to borrow it and pass it on!!!!!!

 

[DaveVmax]

cps voltage was fine and the CPS is mopar part

 

[Ecomike]

cps voltage was fine and the CPS is mopar part

Fine = ???

 

[Ecomike]

I do not see the CTS, MAT or Map sensor listed? Is it still getting fuel now since the last wiring fix?

ok bringing this up again...

still cant figure out this starting issue.

so far everything ive changed...

-all the main grounds plus a new ground from battery to body
-starter relay
-all "hot" main cables
-plugs
-wires
-cap/rotor
-coil
-TPS
-IAC
-starter
-ICM
-CPS
-injector seals
-cleaned the injectors
-check valve went bad so i replaced with in line check valve


just wanted to add that when the truck starts it runs perfect.

 

[DaveVmax]

sorry late reply...

but the CPS was putting out 252ohms

did a fuel pressure test
this was running

and this was off

seems kinda low 29-31psi isnt it supposed to be around 39?

no fuel lines are leaking and the injectors are dry around the seals

 

[cruiser54]

You need to check the CPS VOLTAGE while cranking the engine over, probing the CPS connector with your voltmeter on AC. You should have .5 volts. Post up what you do have BTW.

 

[DaveVmax]

i need to get my volt meter from work tomorrow so it will have to wait. The CPS was a mopar replacement so im having doubts its will be the issue

 

[cruiser54]

i need to get my volt meter from work tomorrow so it will have to wait. The CPS was a mopar replacement so im having doubts its will be the issue

Would be nice to rule it in or out by testing the voltage output.

 

[DaveVmax]

What about the fuel pressure? Seems kinda low no?

 

[Ecomike]

What about the fuel pressure? Seems kinda low no?

29 to 41 psi is normal. One is with no vacuum, the other is at high vacuum like during deceleration? IIRC

I forget the exact conditions. Try it during decel and acceleration, and at idle with no vacuum line attached the FP regulator.

Edit: It is 31 psi with vac hose attached at idle, and 39 psi at idle with vac hose detached. I get 29 to 41 on mine. gauges can vary a little, and pumps a little.

 

[DaveVmax]

yes it was with the vacuum line plugged in