Diagnosing D-Jet Problem...solution & update, All of a sudden...loss of power... Options

[MikeInMunich]

Update...

I'm taking Volker‘s advice and will have the injectors changed. I am pretty sure the car is running too lean. Will have CO tested ASAP and will attempt compensation via increasing fuel pressure to 31 psi, then 32...

Meanwhile, all other basics will be taken care of...valves, timing, fuel lines and filter checked, grounds checked, cap and rotor were already changed by myself, vacuum lines checked, TPS re-set, plugs changed and compression checked. I’ll report back CO and fuel pressure values prior to and after adjustments to the valves and prior to and after swapping the injectors from yellows (for 1.7) to greens (for 2.0).

Thanks, especially to Volker, again.

Mike

[Dave_Darling]

A wide-band O2 meter would be a decent way to get real-time readings of the mixture. That way you could confirm that it is too lean.

--DD

[DRPHIL914]

A wide-band O2 meter would be a decent way to get real-time readings of the mixture. That way you could confirm that it is too lean.

--DD

(IMG:style_emoticons/default/agree.gif) -- pretty sure I said that on post #19 (IMG:style_emoticons/default/poke.gif) - Got mine from Summit Racing, had the O2 bung welded in to the proper place on the Triad and ran the line for the gauge - WOW was I lean- and when the diaphragm on theMPS went bad before it went all the way I knew it was going because I was very rich suddenly- anyway - you wont be guessing---

Phil

[brant]

also,

I wouldn't really increase fuel pressure past 31
just my opinion.

but you can more easily change mixture through MPS calibration (there are actually 3 things to adjust.... not one... at the end of the MPS)

you have to have a wide band to adjust mixture

[MikeInMunich]

I decided to take Volker‘s (Dr. D-Jet‘s) advice and change the injectors from the yellow (for 1.7 liter) to the green (for 2.0) from Bosch. Found a few at reasonable prices, used. Bought 6, 2 were defective.

Car is now running great. MPS is from 1.7 and was restored by Volker. It has a new diaphragm and holds vacuum tightly.

CO value is at about 3.5% and my mileage on my first trip with girlfriend and luggage was about 18 MPG, which was pretty disappointing. Most of that was highway or at least in 5th gear. Thoughts?

I think it’s running too rich and mileage should be about 40% better / closer to 25 MPG. For my European friends, that was 13 liters / 100 km (this is how we measure gas mileage over here).

I purchased 4 MP sensors for 2.0 liter engines for about 60€ apiece. They all worked but gave higher CO values, one being as high as about 5%.

Compression was 116 PSI on 3 cylinders and 123 on the other. Valves were adjusted, though they weren’t off by much a5 all. Timing checked / set at 25 degrees BTDC. Ignition is good. Cap and rotor in electronic distributor were changed. Fuel pressure is still at 29 psi / 2 bar.

Next step, open up MPS and through trial and error adjust to get a lower CO value, goal being 2%. When successful, I hope my mileage is at least 30% better. Gas costs $6 a gallon over here!

BTW. The CO value with the same MPS and the yellow injectors for the 1.7 was 0.5%. The car was running way too lean and quite badly, though I never did determine what was causing the ORIGINAL hesitation.

Thoughts and feedback?

Thanks! (IMG:style_emoticons/default/beerchug.gif)

Mike in Munich
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