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914World.com _ 914World Garage _ Way too rich d jet

Posted by: biggy72 Jul 18 2006, 06:32 PM

So I'm finally going to get a chance to work on my 72 1.7 with d jet a little bit after having it mostly together for the past several months (Been away at school). Any way I just put a new motor in and while trying to hook back up the wiring harness and all of the vacuum lines I'm not sure everything's right. It will start ok, but it won't hardly rev at all and it's running extremely rich. Is there a particular sensor I should take a look at, or do I just need to trace everything back? I've only got a couple days before I've got to take off again so hopefully I can figure it out pretty soon.

Posted by: Rand Jul 18 2006, 06:43 PM

Check the hose to the MPS first. If that's disconnected it will run extremely rich.

If the intake air temp sensor on the plenum is disconnected it will run a bit rich.

If you keep trying to rev it does it clean out any at all?

Posted by: Bleyseng Jul 18 2006, 06:53 PM

Is it timed right?

Posted by: Cap'n Krusty Jul 18 2006, 08:40 PM

Timing won't make it rich. Since this is a fresh install, one might suspect the inlet and return hodses could be swapped. That would give you double the fuel pressure. As was already mentioned, check the MPS to see if it holds vacuum, as well as making sure the MPS hose to the intake plenum is intact and attached at both ends. The Cap'n

Posted by: biggy72 Jul 19 2006, 06:17 PM

Ok I just got done straightening out some fuel line routing and it started easier and doesn't seem as rich, but it's still extremely rich. I noticed that the head temp sensor wire broke so I've got to fix that, but would it make it run that rich? The mps is all wired up and plugged in. I know it was working when I pulled my last motor out. I'm going to go keep working on it, but any ideas would be helpful.
thanks

Posted by: tdgray Jul 19 2006, 06:20 PM

In my exp. you must have all the vac lines routed correctly to diagnose anything.

negotiate that and the fuel lines and then report back.

You'll get it

Posted by: krazykonrad Jul 19 2006, 06:40 PM

Look for vacuum leaks, even where you dont think you have any. I have the same problem with my d-jet, too. I replaced the vacuum line from the MPS to the plenum and the real thin line from the throttle to the dizzy. neither one had obvious lekas, but it made a huge difference. I'm in the process of replacing more lines as I go. I also replaced the throttle body gasket. The rubber parts I replace the better it gets.
Good Luck!
Konrad
72/4

Posted by: krazykonrad Jul 19 2006, 06:42 PM

I forgot to add that clamps on the ends of the line between the MPS and the plenum seemed to help. Also check your intake hoses. that solved a major vacuum leak.
Keep on pluggin!
Konrad

Posted by: Jeff Bowlsby Jul 19 2006, 07:14 PM

TS2 must be plugged in or it will run....RICH...if it runs at all.

Posted by: biggy72 Jul 19 2006, 08:45 PM

TS2 ?? temp sensor? is that the head temp sensor I had the wire break on? I just double checked quite a few things and pulled the plugs. I've got 1 and 2 fouling out badly, but they have spark right after cleaning them up, and 3 and 4 are pretty black. I'm going to get new plugs, and a cap and rotor tomorrow because I know it could use them, but I'm going to go try to trace the temp sensor I broke so I can get it plugged in right now.

Posted by: Bleyseng Jul 19 2006, 09:36 PM

If the head temp sensor wire is broken or not hooked up, good luck getting it to run at all. It makes the ECU go very rich!

Posted by: biggy72 Jul 19 2006, 11:14 PM

I must have a hell of a good set up then because it runs, but rich for 5 minutes or so til it floods out. I pulled the harness apart a little bit ago and I need to fix quite a few wires. I never was a fan of brittle wires but I can't afford a new harness and I think I can fix this one for the time being any way.

Posted by: biggy72 Jul 20 2006, 01:17 AM

Ok it's all rewired, but I think my plugs are so fouled up I can't get them to clear out so i'll get a new set tomorrow and see what it does.

Posted by: ptravnic Jul 20 2006, 07:41 AM

Sounds like you have the initiative. See this link for answers to common (and not so common) D-Jet issues.

http://members.rennlist.com/pbanders/

Enjoy!

Posted by: bob174 Jul 20 2006, 08:09 PM

Tee in a fuel pressure gauge and make sure your fuel pressure is 29 psi.

Posted by: biggy72 Jul 21 2006, 01:15 AM

Well I got stuck on another project today and didn't have time to do much with the car, but late last night I burned off the plugs and got it started. It wasn't rich any more, but it kind of idled at about 3 grand and surged wildly. I'm sure there's some kind of vacuum leak causing it, I just need to track it down. I've got all day tomorrow to figure it out so we'll see.

Posted by: ptravnic Jul 21 2006, 05:45 AM

To find the vacuum leak spray propane around all the connections while the car is running. If it stumbles you found your vacuum leak. I found out my plenum was leaking using this method. That was a beeeaaaaatttttcccchhhhh to isolate - only way I figured it out was using the $5 handheld camping type propane.

Happy hunting.

Posted by: krazykonrad Jul 21 2006, 08:16 AM

Starting fluid/ ether works great for isolating vacuum leaks. go easy on it, espescially close to the intake as burning more than just a tiny bit in the combustion chamber can eventually cause mucho problems. SHold be a couple of bucks in a spray can at any auto parts store.
Best of luck! You'll have vacuum leaks in places that you never imagined!
Konrad
72/4