bad injectors?
Thread Starter
Burning Brakes
Joined: Aug 2010
Posts: 833
Likes: 1
bad injectors?
My 86 has been sputtering when a load is put on the engine, like accelerating/ going up a hill etc. but it idles perfectly. It's like a miss, but on all cylinders and randomly. I have new cap, rotor, coil, plugs, fuel pump, and fuel filter. The injectors are original, so I they might be causing the problems. I'll do a fp test in a min and check all the plugs when it cools down. You guys have any idea what might be wrong?
Burning Brakes
Joined: Jun 2008
Posts: 892
Likes: 1
From: New Smyrna Beach Florida
With my 89, I noticed it ran fine when cold, (in open loop), but when it warmed up is when it seemed to skip. This seems to be the norm.
New fuel injectors made the diff for me. If u have the stock Multecs, the ethanol in today's gas eats them up, so don't put those back in.
What I did was call Jon at fuelinjectorconnection.com like many others have done. See sticky on fuel injectors at top of page C4 Tech/Perf.
New fuel injectors made the diff for me. If u have the stock Multecs, the ethanol in today's gas eats them up, so don't put those back in.
What I did was call Jon at fuelinjectorconnection.com like many others have done. See sticky on fuel injectors at top of page C4 Tech/Perf.
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
Yes, especially under load. Best and oldest check I know of is after dark , have someone apply all the brakes, start the engine, apply more breaks, put in gear rev engine until it is under a slight load, watch engine. If you have cracks in the insulation you will see sparks jumping to ground. Obviously this is somewhat dangerous so be careful. Did I mention applying the brakes and not overreving?
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Drifting
Joined: Aug 2002
Posts: 1,775
Likes: 125
From: Birmingham AL
This very well could be an injector issue. However, eliminate the EGR as a culprit first. Pull the vacuum hose from the EGR and plug the open vacuum line temporarily. Go for a drive and see if the condition still exists. You can also ohm test the injectors for consistent readings and that will sometimes be an indicator of bad injectors.
Burning Brakes
Joined: Mar 2006
Posts: 760
Likes: 1
From: N.W. Arkansas
my 89 was doing the same thing with original injectors in them,,, I replaced mine just this week and boy what a difference,,,, first thing I did was ohm out my injectors, and I found the bad injector only ohming out at 2,,,,, as someone mentioned,, jon hooked me up at FIC,,,, good luck,, rj
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
Might want to swap out the ignition module in the distributor. Less expensive and easy to do compared to injectors. Yours is 25 years old now. Sometimes they can cause gremlins like you're describing. Worth a try.
Racer
Joined: Oct 2003
Posts: 475
Likes: 21
From: CLAREMONT Ca
My 86 has been sputtering when a load is put on the engine, like accelerating/ going up a hill etc. but it idles perfectly. It's like a miss, but on all cylinders and randomly. I have new cap, rotor, coil, plugs, fuel pump, and fuel filter. The injectors are original, so I they might be causing the problems. I'll do a fp test in a min and check all the plugs when it cools down. You guys have any idea what might be wrong?
If you decide to mail your injectors to them but the low cost insurance from the post office.
Last edited by Tact; Jan 5, 2011 at 07:34 PM. Reason: Non supporting vendor
Team Owner
Joined: Jul 2004
Posts: 28,426
Likes: 3,277
From: Hartford WI
Absolutely. Run the car and set the RPMs up with either a brick at the pedal or something. Spray a fine water mist around, not at, the wires and see what happens. Obviously it has to be in total darkness to work.
Thread Starter
Burning Brakes
Joined: Aug 2010
Posts: 833
Likes: 1
This very well could be an injector issue. However, eliminate the EGR as a culprit first. Pull the vacuum hose from the EGR and plug the open vacuum line temporarily. Go for a drive and see if the condition still exists. You can also ohm test the injectors for consistent readings and that will sometimes be an indicator of bad injectors.
Thread Starter
Burning Brakes
Joined: Aug 2010
Posts: 833
Likes: 1
Is there any way to test that? I don't want to just throw parts at it, a new ICM is around $50. I know I need the injectors, so that's why I'm trying those first.
Team Owner
Joined: Jul 2004
Posts: 28,426
Likes: 3,277
From: Hartford WI
Team Owner
Joined: Jul 2004
Posts: 28,426
Likes: 3,277
From: Hartford WI
People have mentioned that the ICM has been tested to be good but replacing it cured problems. Mine too. Get a good Delco one and keep it as a spare.