Still running too rich, help!

[dbeardsl]

I have been working on this problem for several weeks. I have a 74 2.0. For some reason, its running way too rich, un driveable. It idles between 2100 and 2500 rpm, it completely dies if you give it a little throttle, it only revs up if you nearly floor it. I have checked most of the usuals, vacum hoses, mps and tps look brand new inside and measure up right, etc...
anybody have ANY ideas. I pinched off the fuel line to the CSV, didn't change anything. I have tried the idle mixture control on the FI brain, no luck. The idle screw on the throttle body just changes the idle from 2000 to 2600.

Thanks in advance.


[This message has been edited by dbeardsl (edited 11-21-1999).]

[dbeardsl]

I checked the cylnder head temp sensor, its 3400 right now(about 45 degrees F out side). I cant keep it running long enough right now to test it warm. I will try tomorrow.

[Ian Cubus]

I had a similar problem several years ago which turned out to be a misrouted vacuum line. I'm sorry I can't remember exactly which one but I think it was the manifold pressure sensor? The car was a 74 2.0 with fuel injection and was spewing black smoke from the pipe with horrible drivability. I would recheck the vacuum line routing and hose clamp every hose. Next I would check for vacuum leaks just to make sure there is an association between the high idle and running rich. Lastly I would check the fuel pressure. Hope this helps, Ian

[This message has been edited by Ian Cubus (edited 11-21-1999).]

[Dave at Pelican Parts]

Also the timing. The two main causes of high idles in D-jet 914 motors are: 1) Vacc leaks (including mis-routed hoses) and 2) over-advanced timing.

Check the hose diagram on this site for the hose routing, and check the timing article for how to set the timing.

--DD

[Ian_G]

Hey there,

You may or maynot have covered this but the main problem when a MPS goes bad is a WAY TOO RICH running situation. Have you checked the MPS?

If it tests cool, look at FI FAQ, then drill out the rear plug and set the mix there.

I was hesitant about this but it solved my problem of too lean.

Ian

[Ian_G]

I would agree here with Brian. The adjustment is not a linear scale. However if you equip the car with an O2 sensor and air/fuel mixture gauge you can easily dial in the MPS.

I'd also like to note that I did scrape away the epoxy plug. I fitted the largest, best fitting, flat head I bought just for this car and immediateally ripped the aluminum plug. So if you have this experience you can drill into the plug and reveal the adjustment screw. Just cover the adjuster after you are through messing in there.

Peace Ian

[dbeardsl]

Hey, Ian and Brian, Thanks, but if you read my post, it says that I already checked the mps. I popped out the rivets and looked inside, all the seals were good, it was measuring right, and it looked brand new. The best solution is NOT to buy a new one, they are like $300. Just pop the little thing right open and look inside, its pretty simple.

thanks though

[Dave at Pelican Parts]

Well, 3400 ohms is probably somewhat high. Most of the HTSes you can get new today are in the 1500-2000 ohms (cold) range. I picked up a Type III HTS that is about 2500 ohms cold.

These were all measured around 60-70F. I don't *think* they'd get all the way to 3400 ohms at 40F.

--DD