[Dan T]

I have an 83 Spider with an injector problem.

#2 cylinder does not fire well at idle, but does seem to kick in as rpm's increase.

I sent all injectors out to be cleaned, and have just reinstalled them only to find out I have the same problem.

Does anyone know what else would cause an injector to not run properly?

Also, the car occasionally refuses to run at idle.
When I disconnect the throttle position switch, it seems to fix the problem.

I replaced the tps with a used part, and it still does the same thing. Could I have ended up with a second bad unit??? Or, is there something else wrong...



Thanks for the help,
Dan

 

[jonesdds]

What made you think injector to begin with? Couldn't the misfire on 2 be lack of spark in nature? After cleaning the injectors were they tested? Did you reinsert the same injectors into their original sites? I'm not sure what type of injectors your car has nor how they are seated into the intake mines a SPICA with carbs now, but I did redo my injectors in my Ferrari at one point. The bushings were a mess as well as the seals so both were creating a vac leak that I'm sure contributed to poor idle.

I bought new injectors and had them tested and picked the best 8 on that car.

 

[rogerspeed]

I have had problems with #2 on an '83; it was the electrical connection between the socket on the harness and the injector, do not use dielectric grease there (it is an insulator) I wonder if you are missing the ground strap to the plenum?

 

[jcslocum]

Dan, There are a few other things that can be in play here: Vacuum leaks, low compression, bad spark plug and or wires, etc....

If you have a compression tester, that is the best place to start so you (we) will have a good base line for the health of the mechanical parts. If you find a low-ish compression on #2 then a leak-down test is really the next step. Once these are known (at least the compression) you can begin to bottom out other pieces of the system.

Check the rubber boots from the manifold to engine. If they are leaking, then #2 might be running quite lean. In fact, check all hoses and tubes for any cracks or leaks, these engines do not tolerate air leaks at all!

For a few easy things to do, you can certainly change the plug and wire from another cylinder and see if #2 still act up. That could eliminate those 2 parts. Then you start to move into the injection system itself. It is all electrical so cleaning up all grounds and connections can't hurt.

The VVT can stick and create a huge vacuum leak like condition with the cam advanced and the idle will be terrible and stall.

A test light to figure out if the #2 injector is getting signal is also good to have. It's called a Noid light and can be had at most auto parts stores.

Good luck!!!

 

[Huggy]

Dan,

The VVT can stick and create a huge vacuum leak like condition with the cam advanced and the idle will be terrible and stall.

A test light to figure out if the #2 injector is getting signal is also good to have. It's called a Noid light and can be had at most auto parts stores.

Here's the cheapest I could find on search:

List Price: $16.95
Price: $9.68 Eligible for free shipping with Amazon Prime.
Deal Price:
You Save: $7.27 (43%)

Only 4 left in stock (more on the way).
Ships from and sold by Amazon.com.

 

[papajam]

Please keep in mind that there are a number of different noid lights each designed for a specific fuel injection system. Bosch injected vehicles require a noid light suitable for, drumroll please, a Bosch system.

 

[Dan T]

Thanks for the suggestions.

I have had compression checked, and no issues there at all. Have also replaced all vacuum hoses and related equipment.

I have also had valves and timing adjusted. The node light sounds like a good place to start, and also cleaning the plug connection at that injector. I believe the plenum ground strap is intact, but will check.

Do you think it could be related to a main computer malfunction?

Dan

 

[Greg Gordon]

Doubtful it's an ECU (main computer) issue. It is quite possible it's the injector connector on the wiring harness. That's often the problem. Don't ignore the possibility of a spark issue either.

Greg,
Silicone Hose Kits
OKINJECTORS--Gasoline and Diesel Injector Cleaning, Rebuild, Overhaul, and Testing Services

 

[ghnl]

The injectors are batch fired - they all squirt at the same time - not sequentially fired (like the spark plugs). You can thus swap the electrical connectors and see if the fault stays with the injector or moves with the connector.

That said, L-jet is so sensitive to "false air" (intake air or vacuum leaks) you must be 100% certain that is not the issue. Also, a clogged Oil Vapor Separator (OVS) messes up the sump scavanging which mimics an air leak. So, if it hasn't been done in recent memory, consider cleaning out the OVS. Remove it, soak in solvent or squirt some brake cleaning spray into it until all gunk has been rinsed out. Also make sure the attached hoses are intact & attached properly.

 

[Huggy]

Please keep in mind that there are a number of different noid lights each designed for a specific fuel injection system. Bosch injected vehicles require a noid light suitable for, drumroll please, a Bosch system.

Hey Papajam,

This one is Bosch PFI 510597. Do you know if this one is proper for Alfa? I was unable to find other Bosch Part Numbers.

It has two small male pins, from the photo less/about 1/2 " apartl.

Listing is at:Amazon.com: Bosch noid light

 

[Huggy]

Injector Problem

Hey Papajam,

This one is Bosch PFI 510597. Do you know if this one is proper for Alfa? I was unable to find other Bosch Part Numbers. There is actually two, the other part is Bosch2 #J-44603. I can't find the vehicle fit info.

It has two small male pins, from the photo less/about 1/2 " apartl.

Listing is at:Amazon.com: Bosch noid light[/QUOTE]

 

[papajam]

Well, look at that! Two different noid lights for Bosch (guess I've been out of fixing cars for a living for longer than I thought).
I'll guess the 510594 is for a port fuel injection system (PFI). It may or may not work on a Spider L-Jet. But the J-44603 (OTC #6266) looks to be the light for the L-Jet system.

 

[Huggy]

Well, look at that! Two different noid lights for Bosch (guess I've been out of fixing cars for a living for longer than I thought).
I'll guess the 510594 is for a port fuel injection system (PFI). It may or may not work on a Spider L-Jet. But the J-44603 (OTC #6266) looks to be the light for the L-Jet system.

Just had a chat with Amazon, neither noid is app for Alfa. Good Thought though.

 

[jcslocum]

You can just swap the wiring around and see if that move the problem.

 

[Dan T]

Thanks for all of the suggestions! I switched the injector plugs and nothing changed. Then I switched the plug wires, and the problem moved to a different cylinder. I spent $140.00 on a German made set of new plug wires a couple of years ago, and haven't driven the car much since. I am surprised one failed so quickly, but that sure turned out to be the problem.

Dan

 

[ghnl]

Thanks for letting us know you found the problem. Glad it was a fairly easy fix.

Do you have a Volt-Ohm meter? You can use that to measure the resistance of each spark plug wire. The original Bosch spark plug connectors also have a built-in resistance. That can also be measured. I've had one of those fail.