Help - Djet running way too rich Options

[rjames]

I had a similar situation and it turned out to be a bad ECU. After 15-30 minutes of driving, the car would run super rich.

I still question your rebuilt MPS. You said you tested it, but just verifying that it holds vacuum isn't enough. You need the tools to adjust it (tangerine racing) and an AFR meter to dial it in. If the rich running your experiencing is intermittent, than you can probably check the MPS off of your list. But if it's always rich and swapping the ECU out doesn't change anything, then I suspect your MPS needs calibrating.

Quote jrmdir
In rebuilding the MPS, reestablishing the height of the center plunger involves an imprecise measurement. So this could be the issue. There is mention of uncovering the adjustment screw and then calibrating the MPS. But Mr Anders says this requires special equipment. It seems like this adjustment could easily impact the rich/lean situation. Has anyone tackled this calibration without test equipment?

@jrmdir At the very least you need the tools to adjust the MPS and and an AFR meter to set the MPS correctly.

[Halfnelson]

I had a similar situation and it turned out to be a bad ECU. After 15-30 minutes of driving, the car would run super rich.

I still question your rebuilt MPS. You said you tested it, but just verifying that it holds vacuum isn't enough. You need the tools to adjust it (tangerine racing) and an AFR meter to dial it in. If the rich running your experiencing is intermittent, than you can probably check the MPS off of your list. But if it's always rich and swapping the ECU out doesn't change anything, then I suspect your MPS needs calibrating.

Thanks Robert - the MPS hasn't been rebuilt, still the original and holds vacuum - or at least was. Will double back and recheck.

How did you diagnose that it was the ECU? There seem to so many potential culprits and I had hoped these were already ticked off the list.

[rjames]

I had a similar situation and it turned out to be a bad ECU. After 15-30 minutes of driving, the car would run super rich.

I still question your rebuilt MPS. You said you tested it, but just verifying that it holds vacuum isn't enough. You need the tools to adjust it (tangerine racing) and an AFR meter to dial it in. If the rich running your experiencing is intermittent, than you can probably check the MPS off of your list. But if it's always rich and swapping the ECU out doesn't change anything, then I suspect your MPS needs calibrating.

Thanks Robert - the MPS hasn't been rebuilt, still the original and holds vacuum - or at least was. Will double back and recheck.

How did you diagnose that it was the ECU? There seem to so many potential culprits and I had hoped these were already ticked off the list.

My mistake- I thought your MPS had been opened up.
I figured out it my ECU was bad after testing all of my other components and eventually swapping it with a known good ECU. See if you can find someone who will let you borrow theirs. You're lucky in that there seems to be a ton of used 1.7 ECUs for sale at any given time. 2.0 ECUs can be hard to find.

[Rand]

What was the difference in idle when you pulled the hose off at the MPS? Just give me that.

[rjames]

What was the difference in idle when you pulled the hose off at the MPS? Just give me that.

Would it even run? IIRC, pulling the hose off would just cause it to go super lean, so if it ran I guess it would tell you that something else in the system is causing an uber rich condition, but it wouldn't rule out the MPS as a contributor.
If it doesn't run, what would that tell us?

If it's an intermittent issue or doesn't happen until the car warms up a little (I'm still not clear if that is the case here) then it's probably not the MPS. I haven't run across intermittent issues, or issues that happen only when the engine is cold or only when warm that ended up being the MPS. Seems like when it's the MPS that's the problem, the symptoms there all the time.

[emerygt350]

Just out of curiosity, have you checked which injectors are in there? Mine came with 1 1.7 injector and on a 2.0 that means one really lean cylinder. Some fool might have put 2.0 injectors in yours.

[Halfnelson]

Just out of curiosity, have you checked which injectors are in there? Mine came with 1 1.7 injector and on a 2.0 that means one really lean cylinder. Some fool might have put 2.0 injectors in yours.

OK - I'd never even considered the injectors could be wrong but...

[Halfnelson]

Lots of questions spring to mind like how it was even running with the wrong injectors in?

The number seems to end 1120 07 (although I couldn't quite see) - which doesn't look like 2 litre green injectors?

Next step is where can I find either the correct yellow injectors or a new set of compatible alternatives?

[emerygt350]

I have 1... And it is yellow.


I bought those new injectors, Standard motor products. The guy that rebuilds injectors tested them and found them to be quality. Not sure what the 1.7 version is labeled as. Fj67 is the 2.0

[emerygt350]

The left side is the 2.0

[steuspeed]

Wrong injectors.. amazing! I bought a set of Standard Motor Products injectors for my 2.0 Outlaw and they sure look nice. Get them if you can't find OEM yellow injectors. RockAuto had the best price I could find.

[ChrisFoley]

Those look like 1.8L injectors, for L-Jet. Someone had to mess with the wiring harness to use those.

[emerygt350]

Wow, the plot thickens.

[Rand]

What was the difference in idle when you pulled the hose off at the MPS? Just give me that.

Would it even run? IIRC, pulling the hose off would just cause it to go super lean, so if it ran I guess it would tell you that something else in the system is causing an uber rich condition, but it wouldn't rule out the MPS as a contributor.
If it doesn't run, what would that tell us?

If it's an intermittent issue or doesn't happen until the car warms up a little (I'm still not clear if that is the case here) then it's probably not the MPS. I haven't run across intermittent issues, or issues that happen only when the engine is cold or only when warm that ended up being the MPS. Seems like when it's the MPS that's the problem, the symptoms there all the time.

Pulling the MPS hose does NOT cause lean, it causes full RICH. True, it should not run, it should immediately choke and die. I wasn't necessarily suggesting the MPS as the problem, but ANY time Djet runs rich, check the MPS because a bad diaphragm or leaky hose/connection is a common cause of running rich! I can't think of another test that takes two seconds that tells so much about fuel mixture. IF it didn't change, it would have absolutely been MPS (or not) in 2 seconds! Always do the quick tests to quickly rule things out in early troubleshooting!

[rjames]

What was the difference in idle when you pulled the hose off at the MPS? Just give me that.

Would it even run? IIRC, pulling the hose off would just cause it to go super lean, so if it ran I guess it would tell you that something else in the system is causing an uber rich condition, but it wouldn't rule out the MPS as a contributor.
If it doesn't run, what would that tell us?

If it's an intermittent issue or doesn't happen until the car warms up a little (I'm still not clear if that is the case here) then it's probably not the MPS. I haven't run across intermittent issues, or issues that happen only when the engine is cold or only when warm that ended up being the MPS. Seems like when it's the MPS that's the problem, the symptoms there all the time.

Pulling the MPS hose does NOT cause lean, it causes full RICH. True, it should not run, it should immediately choke and die. I wasn't necessarily suggesting the MPS as the problem, but ANY time Djet runs rich, check the MPS because it's so easy (and a bad diaphragm will absolutely cause rich running). I can't think of another test that takes two seconds that tells so much about fuel mixture. IF it didn't change, it would have absolutely been MPS in 2 seconds! Always do the quick tests to quickly rule things out in early troubleshooting!

Yup- I had it backwards. After all the DJet and MPS troubleshooting I’ve done in the last two years I don’t know how I got that one wrong! (IMG:style_emoticons/default/unsure.gif)

[Rand]

Yup- I had it backwards. After all the DJet and MPS troubleshooting I’ve done in the last two years I don’t know how I got that one wrong! (IMG:style_emoticons/default/unsure.gif)

We've all gotten things wrong. My biggest point, is quick troubleshooting. I've seen people spend hours chasing rabbit trails that could have been ruled out in seconds! It hurts every time.

PS: Checking out your music (IMG:style_emoticons/default/smile.gif)

[Halfnelson]

Those look like 1.8L injectors, for L-Jet. Someone had to mess with the wiring harness to use those.

My guess is not 1.8 as they are more of a blue / green IIRC but also the whole shape of the injector plug looks different to the 2.0 and 1.7 injector plugs. Could be someone try to find a suitable alternative or ordered the wrong part? The FJ67's etc aren't available in Europe.

[emerygt350]

The one you are looking for is the fj114. 59 dollars on Amazon.

[Halfnelson]

I'm resurrecting this thread if that's ok so hopefully it'll add some context / back story.

The gist is my 73 1.7 on standard Djet would run ok for a short period of time - then flood. It was an intermittent problem that got so bad petrol is now actually spewing out of the exhaust.

After discovering I had the wrong injectors fitted (way too much fuel being delivered) I had a set of new FJ114. I hoped this would crack it - but after starting and ticking over for a short while... it started to run rough, smoke cough and die. Turning the car over then results in petrol spewing out of the exhaust again.

Short recap of work done includes: all new vacuum lines, CHT sensor replaced, MPS tested, fuel return tested, cold start injector disconnected and bypassed, new fuel pump fitted and fuel pressure tested, new coil fitted.

The question is - a year down the line - what next? And what could be causing such a catastrophic over-fueling - it's not just running rich - there is fuel pissing out (IMG:style_emoticons/default/headbang.gif)

[JeffBowlsby]

Have you checked your CSV for leakage?