Hard to start and dies frequently

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OKinNC

NAXJA Forum User

Location

Clayton, NC

• Nov 4, 2008

• #1

I have a fuel injected 89 XJ with a 4.0 six cylender and it started dieing whenever I let off the gas to turn or stop. It will start right back up but if it sits for very long I have to pump the gas a lot to get it started. When I turn the key on I hear the fuel pump engage. Any Ideas?

 

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dinorl007

NAXJA Forum User

Location

dublin, va

• Nov 4, 2008

• #2

check your fuel pressure? if u search i am sure it has been covered, or try pming one of the senior members, have u checked all the simmple stuff, plugs, cap rotor, all the plug in tight, no oose wires? does the cel come on? these are wuestions that will be asked before someone can give u advice hth

 

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OKinNC

NAXJA Forum User

Location

Clayton, NC

• Nov 4, 2008

• #3

I've check cap, wires, and plugs. I don't see any obvious problems with vacuum lines or wires. I also tested the cps and it read 235 Ohms. I know I have fuel at the fuel rail but don't know how much pressure.

 

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neonrog

NAXJA Forum User

Location

Tooele

• Nov 5, 2008

• #4

Pumping the gas with a fuel injection system does nothing but could confuse the system.

CPS is in spec... And dinorl007, Renix 87-90 doesn't have a Check Engine Light...

 

Smittty9785

NAXJA Forum User

Location

SE Portland Oregon

• Nov 5, 2008

• #5

fuel pump

 

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birchlakeXJ

NAXJA Forum User

Location

Melrose, MN

• Nov 5, 2008

• #6

Start by testing fuel pressure at the schrader valve on the fuel rail both running and not running (dynamic/static) and compare your readings to factory spec. If that checks out, I'd test the throttle position sensor.

 

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OKinNC

NAXJA Forum User

Location

Clayton, NC

• Nov 6, 2008

• #7

I tested the fuel rail pressure 39 psi not running 30 psi running so I don't think the fuel pump is the problem. I noticed while checking the fuel pressure that once I got it running it would idle fine and then just shut off without hesitation as if someone turned the key off. It would start back up pretty easily and run a few minutes and do the same thing.

 

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OKinNC

NAXJA Forum User

Location

Clayton, NC

• Nov 6, 2008

• #8

Tested throttle position sensor .8v closed 4.8v wide open. That's good right? Any help on what to do next?

 

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OKinNC

NAXJA Forum User

Location

Clayton, NC

• Nov 6, 2008

• #9

I tested crank position sensor voltage. It was .183 vac

 

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OKinNC

NAXJA Forum User

Location

Clayton, NC

• Nov 9, 2008

• #10

In case anyone was interested I replaced CPS didn't solve the problem. So I replaced the ignition coil, distributor cap & rotor, spark plug wires, MAP sensor, and fuel pump ballast resistor. One of those things fixed the problem.