vbatla

I've sealed the intake tubes. Cleaned the MAF with MAF cleaner. Checked for any additional vacuum leaks. I've been using techron in the tank to clear any injectors that might be clogged. I put seafoam in yesterday to see if that helps. I've been paying closer attention to the symptom to see if I can isolate the cause. Once warm and accelerating over 50% pedal there still is a hesitation. If I pull back on the gas, it clears up. So it's directly related to the amount of fuel being introduced. I don't have a spare MAF but am looking for a place to get this one tested. the O2 was replaced about 100k ago. Tom at 928 INTL thinks that it's clogged injectors. Even with the miss it still runs strong so the plan is to keep running injector cleaner through the tank and perform other needed maintenance (ball joint boot, & MM's) and see if there's any improvement. I won't be able to do the MM's til after Memorial Day so the cleaner will have time to work. I had an issue a few months back with the gauges. They were jumping all over the place, including the speedo. It turned out to be a fuse that wasn't making good contact. I Have a feeling that this could be a connection issue. I read somewhere else on the forum that someone had a similar problem. I believe they replaced injectors, wires, MAF, O2, Temp ll, Dist, Rotors and Coil to no avail. When R&Ring the dash he noticed that there was a multipin connector that wasn't making good contact and it just so happens, it was the one to the fuel pump. He cleaned it and that finally took care if the problem. That'll be the last resort for me. I'm going to look through the wiring diagram to see if there are any fuses/relays that need to be looked at as well. I'll keep you posted. Thanks again for all of the responses. This is a great forum!

dprantl

100k miles is too long for an O2 sensor...

Dan
'91 928GT S/C 475hp/460lb.ft

vbatla

I'm going to replace the O2 when I get a chance but until then, here's the latest. I did ohm the Temp II. When the the car is running great (cooler) both contacts ohm out to around 650. When hot, and missing/hesitation, they both ohm out to 250 - 220. It appears to be functioning correctly. There are 2 contacts on the temperature sending unit. the wide one changes resistance causing the temp gauge to move up when the temperature rises. When I tried to ohm out the smaller one it came up with an open circuit. Is this supposed to be varying resistance as well? I didn't ohm it out cold but will tomorrow. Have a great Memorial Day Weekend!

vbatla

Update - I've looked at the plug wires at night many times. Then I read, here on the list, to try spraying a light water mist on the wires to see if any lightning appears. Well, lots of lightning with the mist. I could even detect a change in the way the engine ran while misting. Guess it's time for new wires. Any recommendations? thanks

Giovanni

I went back to stock wires after a set of nology wires that barely lasted a few years.

Calgary Ole

New stock wires on my 90 S4 came with all the clips and fit perfectly with little hassle. Wish I had new caps and rotors at the time as everything was off and could of been changed at the same time.

Mrmerlin

I suggest that you spend the extra cash and get the Beru plug wire kit.
Its expensive but it will last more than 10 years , so its not really a cost issue if you figure in how long you dont need to mess with things.
It comes with 4 coil wires and all of the other leads have new ends, and they are already size fitted and insulated, Simply put the best choice IMHO

GlenL

Alternative:

Get just the wires and re-use the ends. They screw on/off and don't go bad.

I did this a few years back on my 944 and the guy offered them for 928s as well. I do wonder if they are still available. Saved big money and did the job.

vbatla

Thanks for all of the responses. I've got an email into Mark Robinson to see if he still makes the sets with Beru wilre. Have any of you bought from him? The last set I put on was the Beru OEM which was about 100k ago, approx 10yrs.

vbatla

I ohmed my existing caps; they're in a range of 2740 - 2860. Are they toast?

Mrmerlin

IIRC they should be right at 3K ohms

vbatla

Follow up: This issue has finally been resolved. New plug wires did the trick. The old ones looked to be in great shape. After Inspecting them with the engine running in the dark while spraying water on them proved otherwise. The addition of one of Porken's EZF'r superchips made it even better. I've had this car since 95 and it has never run smoother. Thank you all for the help!

vbatla

Follow up: Lizard931, I set the MAF with Porken's Blinkr. The original setting was 126 Ohms. the adjusted setting is 536 Ohms. I can't emphasize how much of a difference that made. Perfect idle, unbelievable acceleration and it even changed the sound of the engine. Simply amazing....