Rough engine-Cross-fire Inj.

[mmsss]

A bit of history: 82 model that sat too long without running. The hose connecting the fuel pump to th line disentegrated. I replaced the hose, tank sock, cleaned the tank, changed the fuel filters, put a kit in the cross-fire injection system, new plugs, wires, dist. cap and rotor.

Problem: Even though the car was running fine when it was parked before the hose incident, I can't get it to run smooth now. It runs like I have crossed plug wires. I have checked the wires three times and am certain they are correct and that there is continuity. I can see that the injectors are squirting gas into the throat. Any help will be appreciated. Thanks
Monte

 

[JonM]

It could be one of 20 things...check the wires runningto the distributor. Not the plug wires but the other smaller ones on the side. Check for wear. It could be the module inside the distributor. Could be a vaccum leak someplace. When you turn the key on (not started), look at the injectors, anyone of them leaking? Does it run rough both warm and cold? Check the fuel return line, see if its clogged.

You may also want to post this and do a search at the crossfire site

http://www.crossfire.homeip.net:81/cftest/default.asp

 

[mmsss]

Check for wear where? (That doesn't sound right!) I hadn't thought of the vacuum line part, I'll check that out. How can I check the return line? I didn't think of that either but it could be a possibility due to the disintergration of the fuel line in the tank.

Thanks for the suggestions!!

Monte

 

[JonM]

Check for wear or crud on the connections running into the side of distributor.

Make sure you check all the vaccum lines including the small ones (they get very brittle) running into the egr valve.

To check the return line, you need to disconnect the line at the gas tank...and the same line at the cannister...see if you can blow air through it.

I would suggest if you are going to do your own work...get a manuel...its worth every penny


http://www.helminc.com/helm/homepage.asp?r=

Shop manuel will cost you 75 bucks

 

[mmsss]

Thanks,

I already have the GM shop manual but it doesn't address this problem. I also have an assembly manual for the car. We restored it, but hten didn't drive if for about a year and now I've got a lot of work to do to get it back in shape.
I'll do the other checks this weekend. I have to go out of town tomorrow and will be gone until Fri. so I won't be able to get to work on it until the weekend.

Monte

 

[wishuwerehere82]

If it ran fine before you changed the filter, then something in the fuel system is clogged with a piece of the hose rubber.

I would check your fuel pressure regulator on the rear TB and your injectors for blockage as well as the IAC motors for operation.

Make sure you distributor cap is sitting square on the casting, they are easy to put on with one side cocked up a little. And make sure your plug wires all snap onto the studs on the plugs and distributor cap all the way.

 

[geekinavette]

IACs and EGR valves can get "sticky" after sitting for too long. Do an idle vacuum check...as I recall you should see something like 17" Hg at idle. You wouldn't believe how bad it will run with an EGR that's stuck open just a little.

Fuel pressure spec is 10-13 PSI. Also verify the ignition timing...6 deg BTDC (make sure the EST bypass is disconnected!)

Bill

 

[wishuwerehere82]

Just curious, what kind of a "kit" did you put on the crossfire injection system?

 

[Mr. Chuck]

Inactivity / storage bring other causes for rough engine or poor performance, here are some of the causes I have found, in no special order:
1. vacuum lines (area near distributor, top of engine) eaten part way through by mice caused rough idle, loss of vacuum to open head light doors.
2. electrical wires part of ignition and related components on top of engine near distributor eaten through.
3. Read computer error codes that have been experienced, may direct you to malfunctioning components.
4. check for loose or splits vacuum lines at connection to varies components that monitor engine operations that are feed into the computer command control system.

 

[mmsss]

Pete,

I put in a gasket, o-ring and filter kit and it came with the diaphrams. I think I replaced everthing in the TB except the injectors. I can't remember whether I got it from Mid-America or someone else.
Monte

 

[kjfassoc]

Mine sat for a long time also, with the help of these folks on this forum it runs pretty good, I had to clean the injector filter screens several times, the crude in the fuel lines takes a while to clean itself out. You will be shocked by how much collects in a short period of time

 

[Mr. Chuck]

You indicated that you performed a continuity test on the sparl plug wires; how did you perform said test? Given the different kinds wire cores (conductive material) some additional tests may help to find a bad wire. I find that if you use one of the clip-on type of timing light (I like the Sun model 7501) an inductive style that uses 12 vdc from the car battery. With car running, test each respective spark wire (clip pick-up close as possible to the plug) a wire with defective / broken core material may give a lower voltage spark at the plug or a weak or intermittent timing light flash. In the old days we would just disconnect one plug wire at a time to look for the one that had the smallest negative or no effect on the engine idle speed or smoothnest. If the problem is damaged or defective spark plug wire insulation, look to do a visual test at night with engine running, work light off and look for wires laying against or close to bare metal surface. Move the wire away from the surface with a non-conductive tool or dry length of wood dowel and look for changes in engine idle speed or smoothing out. You may even see a electrical discharge as you move the spark plug wire away.

 

[mmsss]

Ok, here's what I have found out so far. I had one bad plug but when I replaced it, it didn't help the problem. I can't find any vacuum leaks.

Now for the interesting part. When i unplug the left injector, the engine will idle smooth and runs around 2000 RPM and I don't have a check engine light. It shows normal vacuum on my tester. When I plug the left injector in and unplug the right injector, the engine will idle a little rough and I have the check engine light. erratic vacuum. When I plug both injectors in, the engine will not idle, but will run rough at higher rpm's. Low vacuum.

Any other ideas out there what my problem is ??

Thanks,
Monte

 

[wishuwerehere82]

Start from scratch. Fuel pressure,Spark Timing,TPS adjustment,TB balance. Here's a tune up how-to. It's the only way to make sure everything is working properly.

http://corvettefever.com/techarticles/4688/

 

[mmsss]

Thanks,
I've checked the TPS, timing and fuel pressure. I haven't checked the TB Balance yet. I'll have to check outhow to do that.

Monte

 

[wishuwerehere82]

It's quite possible that you have something clogged in that left injector obstructing the flow.

 

[mmsss]

I may have a partially clogged injector because the cone does't look as smooth as the one on the right when I have a timing light. I am also wondering about my ECM. I have gone back through the diagnostics in the book and the ECM won't throw any codes when I unplug the TPS or MAP sensors. I'm not sure about the EGR valve either. I can't see that it moves. It seems to be up all the time. I had the engine running with just the left injector plugged in and the book said to push up the diaphragm up from the bottom but it won't move up. There's so much that can be wrong that I'm about to give up on the POS.

Monte

 

[wishuwerehere82]

You can check the EGR by unbolting it and hooking it up to a vacuum source(suck on it) and see if the diaphragm is moving the plunger up and down. You can move it by pushing in on the plate under the valve to see if it returns to the shut off position.

You can check the TPS by putting an Ohm meter between the center terminal and the outer terminals. On one side your resistance wil go from 12K to 0 and the other will go from 0 to 12k. The original ones are 9 Kohms but the voltage slope still works the same. Set your TPS for .525V at idle.
Don't count out your ECM yet, it usually works or not, there is usually no in between.

 

[mmsss]

I'll take off the EGR tomorrow if I have time. I checked the voltage on the TPS and it read 5.61V. Are you sure it needs to be set a .525. I thought the book said between 4V and 6V. I'll check the resistance on the TPS tomorrow too.

 

[wishuwerehere82]

Yup, .525V +or-0.025V between the center and lower wires (Black and Blue) at 650 RPM. 0.530V is OK. When you open the throttle to wide open the voltage will be between 4.50-5.0 Volts. The ECM should throw a code if the voltage is too high or too low.
Also, since the TPS is on the rear TB the throttle is set to control that TB, that is why balancing the TB's is important. Otherwise, the front TB will be running lean or rich compared to the TPS sensor. There's only about 1/16 of a turn of the balance screw sensitivity between being in and out of balance. It's very sensitive. Get a good water manometer or vacuum gauge to make it easy. 2 of them makes it a piece of cake since you can see the difference between the two while you make the adjustment.

To test the MAP sensor run the engine and unplug the vacuum hose to the TB. The engine should die immediately.