jeeptorino68
NAXJA Forum User
- Location
- Lebanon OR
Should there be a ballast resistor under the hood somewhere?
-
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89 2.5 4cyl wont stay running, fuel?
- Thread starter jeeptorino68
- Start date
8Mud
NAXJA Forum User
- Location
- Central Germany
One issue I've seen is there are around six connectors between the fuel pump relay and the fuel pump. I've seen a corroded connector melt down and starve the pump of sufficient current. Probably wouldn't be a bad idea to check the fuel pump ground also.
Some of those replacement pumps have the wrong colored wires, easy to get a fuel level sender wire crossed with a pump wire.
When I was troubleshooting mine I actually ran a hot wire all the way back to the tank and used that for pump power. That is when I figure out my issue was the wiring/connectors and not something more exotic.
The TBI does have an IAC, if it dies when you let your foot off the gas the IAC is likely the cause.
I'd also have a hard look at the ignition, a very weak spark can fool you into thinking it is a fuel issue.
No ballast resistor I know of, but a really bad connector can cause just about the same issues.
Some of those replacement pumps have the wrong colored wires, easy to get a fuel level sender wire crossed with a pump wire.
When I was troubleshooting mine I actually ran a hot wire all the way back to the tank and used that for pump power. That is when I figure out my issue was the wiring/connectors and not something more exotic.
The TBI does have an IAC, if it dies when you let your foot off the gas the IAC is likely the cause.
I'd also have a hard look at the ignition, a very weak spark can fool you into thinking it is a fuel issue.
No ballast resistor I know of, but a really bad connector can cause just about the same issues.
Jeep Driver
NAXJA Forum User
- Location
- Parrottsville
No ballast resistor on the 2.5.
jeeptorino68
NAXJA Forum User
- Location
- Lebanon OR
Some great info the 8mud, I was looking underneath yesterday and someone had bypassed some of the wires around the fuel pump connector at one point, I will inspect those closer too
- Location
- MilkyWay Galaxy
I have about a 20 Ft jumper I made up with spring clamps for the battery and a new GM weather pack connector on the other end I use for testing the installed fuel pumps to see if it is wiring. It uses a new direct ground and 12 volt feed at the same time.
jeeptorino68
NAXJA Forum User
- Location
- Lebanon OR
back to working on this a bit.
it turns over, and sputters but wont catch and run, occasional backfire out of the intake.
the fuel pump relay clicks, and i can hear the pump hum before i crank. if i bypass the relay with power straight to the 87 pin for the fuel pump, the pump runs for a couple seconds, pauses for 10 or 15 or more, then runs a couple seconds... is this normal?
there still seems to be no fuel to the TB, both supply and return lines are dry.
what about timing? best way to check?
it turns over, and sputters but wont catch and run, occasional backfire out of the intake.
the fuel pump relay clicks, and i can hear the pump hum before i crank. if i bypass the relay with power straight to the 87 pin for the fuel pump, the pump runs for a couple seconds, pauses for 10 or 15 or more, then runs a couple seconds... is this normal?
there still seems to be no fuel to the TB, both supply and return lines are dry.
what about timing? best way to check?
- Location
- MilkyWay Galaxy
Fuel pump outlet hose in the tank may be bad, leaking fuel coming out of the pump back into the tank, or the pump check valve is bad.
Assuming as you said the pump runs for a bit (there is a timer circuit in run, till the engine is running to prime the system) but no fuel is in the fuel rail lines?
Timing is not adjustable, the ECU controls it.
This, 1989?, has a fuel tank pump right? The older like 84-? TBI rigs had an old style mechanical fuel pump run off the cam shaft mounted to the block.
Is there a fuel pressure test port on the supply to the throttle body?
Is there a fuel pressure regulator/check valve on the return line from the TBI to the gas tank? If yes, is it bad?
Assuming as you said the pump runs for a bit (there is a timer circuit in run, till the engine is running to prime the system) but no fuel is in the fuel rail lines?
Timing is not adjustable, the ECU controls it.
This, 1989?, has a fuel tank pump right? The older like 84-? TBI rigs had an old style mechanical fuel pump run off the cam shaft mounted to the block.
Is there a fuel pressure test port on the supply to the throttle body?
Is there a fuel pressure regulator/check valve on the return line from the TBI to the gas tank? If yes, is it bad?
