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> I'm slightly confused!, I know, whats new???
mike_the_man
post May 4 2004, 11:13 AM
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I need to run my theory by somebody that knows more than I do. I think that my 914 2.0L with F.I. is running way too rich. If I set static timing to 0, and timing at 3500rpm to 27, it runs like crap. I've checked all of my timing marks about 5 times, and they're all correct.

Now, if I set my static timing to 27, which would make timing at 3500rpm about 54, the car runs pretty good. I realize that this is way too advanced. So, if the car is running way rich, would advancing the timing make it run better? The way I'm thinking about it, if the car is dumping way too much fuel into the combustion chamber, it needs to fire earlier in the combustion stroke to burn most of the gas. Does this make sense?

Next question, why is my car running rich? Almost everything has been replaced. Could a mis-adjusted MPS make the car run rich at idle?

Thanks, I'm oh so confused! (IMG:style_emoticons/default/blink.gif)
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TheCabinetmaker
post May 4 2004, 11:21 AM
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Is it possible that you have the plugs wires crossed? Are you sure you have the timing light on #1? I don't think advancing the timing would solve a rich running situation. The ecu idle mixture "could" make it rich at idle.

Curt
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nebreitling
post May 4 2004, 11:35 AM
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not to beat what must be a dead horse to you, but are you finding TDC by the timing marks on the fan? are you sure that these timing marks are correct?

i don't know more than you do, but i don't think you could have 54 degrees of advance and a car that still runs well, no matter how rich it is.

i assume that your ignition is all sorted...?

-fuel pressure?
-trigger points?

mps can do some crazy things, but not 54 degrees crazy...

sounds like you need to start from square one and go through things ULTRA-methodically.
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mike_the_man
post May 4 2004, 11:50 AM
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I've checked plug wires multiple times. Everything looks good. Also, I've checked top dead center by using the mark on the fly wheel, the mark on the fan, the mark on the dizzy, and pulling a plug to make sure that piston #1 is at the top of it's stroke. Everything seems to line up. Timing light is on #1, fuel pressure is good, trigger points are new, mechanical advance appears to be working. Adjusting the ECU idle mixture does make a difference, but it still runs like crap. Just a little better or a little worse depending on whcih way I turn. I'm really stumped! (IMG:style_emoticons/default/sad.gif)
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TheCabinetmaker
post May 4 2004, 01:04 PM
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Mike, what pressure are you running at?
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mike_the_man
post May 4 2004, 01:38 PM
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Just under 30 PSI. 29, I think.
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TheCabinetmaker
post May 4 2004, 01:51 PM
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29 is gud! Can you give us more symtoms than just "runs like crap"? That's kinda vague. Need more input! (IMG:style_emoticons/default/smile.gif)
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mike_the_man
post May 4 2004, 01:59 PM
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I guess that is kinda vague, isn't it. When I time it to where it should be timed, 27degress at 3500rpm, the car pops and backfires out of the exhaust. it stumbles and idles very poorly. When the car is under load, it starts to pop and backfire even more.
As the car warms up, it idles a little better, but still not good. I pulled the plugs and they are very black and sooty, and smell a little like gas. All in all, it runs like crap.
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TheCabinetmaker
post May 4 2004, 02:38 PM
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QUOTE(mike_the_man @ May 4 2004, 02:59 PM)
I pulled the plugs and they are very black and sooty, and smell a little like gas. All in all, it runs like crap.

Then you are definitely running rich. Forget the timing for now. Have you put a vacuum gauge on the mps? I know you said you replaced all the components, but I'll bet the new mps was not brand new, but used. Right? Eliminate one thing at a time.
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mike_the_man
post May 4 2004, 03:11 PM
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MPS holds a vacuum, but I replaced the diaphragm and re-calibrated it per Brad Anders web page. It could definately be the problem, the inductance meter that I used was an older one. But, it runs like crap at idle as well, and the MPS doesn't affect idle, correct? It seems to be running way rich across the whole range. What can cause that?
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Dave_Darling
post May 4 2004, 03:27 PM
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The MPS does indeed affect idle.

Check the head temp sensor--at the ECU connector!! It's a good idea to check things from the actual ECU connector, because sometimes it's the wires to the components that have problems. (Tony Bray on the Rennlist found this out with a buddy's 912E that ran like crap.)

Not sure on your timing deal. I said all I could think of last time...

--DD
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lapuwali
post May 4 2004, 03:38 PM
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Have you checked the vacuum connection at the distributor?

Speculation here, as I don't know D-Jet very well: could the MPS be confused enough by a vacuum leak to make the mixture rich? If the vacuum canister on the distributor isn't working, that could (therefore) mess up both the ignition timing and the mixture.
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TheCabinetmaker
post May 4 2004, 03:50 PM
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Dave, would you explain the procedure for this, or is it at Brad Anders site?
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mike_the_man
post May 4 2004, 04:02 PM
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Good idea Dave. It's a new CHT, but I haven't checked the connections at the ECU.
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Dave_Darling
post May 4 2004, 09:55 PM
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Due to the way the ECU is mounted, you have to remove it from the car. Then you remove the screw that clamps the cable to the housing, and slide off the plastic cover. Then you can reach in and unplug the ECU connector. Dig out your Haynes book and look for the pin number for the CHT sensor, put one probe from your voltmeter on that pin and one on the engine block. That measures the resistance of the sender through the wiring harness, so any wiring or connector faults will show up in the test as well.

--DD
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Bruce Allert
post May 4 2004, 11:16 PM
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CHT is # 13.....

I had this exact same problem. I'd time the car & it'd run very bad until I moved the dizzy (& it must've been to the 54 degrees Mike is speaking of). I checked all the electronics and repalced the CHT along with the TPS and FI trigger points in the dizzy. Since I had to take the dizzy out to re-do the trigger points I had thought that I'd originally installed it wrong. Will the car still run it it is 180 out and timed at 54 BTDC? (IMG:style_emoticons/default/idea.gif)

......b
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mike_the_man
post May 5 2004, 08:57 AM
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Bruce,

Have you fixed this problem? Did your car run with the dizzy 180 degrees out? Sounds like it could be my problem... I'll be checking that out tonight.
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Bruce Allert
post May 5 2004, 09:13 AM
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Mike, I'm not completely sure that it is possible, DD could prolly answer better but, I did take it out quite a few times. I do know that I spun it 180 & re-installed it & was able to bring the timing down to its 27 BTDC mark. Ran great then! Can't hurt to try it, eh? Ae you sure that your 27 degree mark is correct? I used the Pelican print out to mark mine.

...........b
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mike_the_man
post May 5 2004, 09:31 AM
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I'm 99.999% sure that my timing marks are correct. So, when you say that you spun it 180 degrees, do you mean the rotor, or the dizzy body? I'm assuming the rotor, right? Can't it only go in one way, because the dizzy shaft has a tang on the bottom that is offset so it can only go in one way, I think. Or am I just blowing smoke out of my (IMG:style_emoticons/default/bootyshake.gif) ?
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Dave_Darling
post May 5 2004, 10:08 AM
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It is designed so that it should be able to go in only one way. Unfortunately the distributor doesn't know this, and will occasionally be stubborn enough for the drive tangs to go into the driveshaft 180 degrees out.

--DD
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