I have been through many problem with my 24v E30 and finally got the engine professionnally rebuilt. Note that have 24lb/hr injector, 3,5 inches MAF with silicone elbow, cone filter with heat shield and head light delete cold air intake and OBD1 intake. Last winter I also installed a new AEM Wideband AFR.
Last monday, got the car retuned on the dyno due to the freshly rebuilt engine. Got about 1500 miles on it before getting it tuned. The car was pulling nice numbers on the dyno. Right after the dyno tuning session, on street runs, it was showing about 12.5 to 12.8 AFR on WOT pulls which is correct. After this, I let the car for about 15 minutes and now on WOT pull it was showing Around 14 AFR! the engine and intake were kind of very hot when touching it. We let the car cool down for about an hour to let the intake and everything cool down. I got out on the highway and got nice 12.8 AFR WOT pulls. I again let the car sat for 15 min and went again on the street. I got 14 AFR on WOT again!
Other than that the car runs great. THere is no knocking sound when the AFR is leaner but I'm pretty sure I can feel a drop in power.
The AEM AFR Gauge are autocalibrating and I leave the cycle complete when turning ignition on before starting.
One thing to note is that the fuel tank purge valve is not hooked up. The tank is presently vented to atmosphere right after the charcoal canister, the purge valve is still there and the TB nipple is capped. (My fuel tank was pressirizing itself on hot track days)
The tuner told me that it could be the Engine coolant sensor, the IAT sensor or the MAF that is providing the DME Erratic data. He said that I should check the data with a scanner before replacing any parts, and I'm also thinking the same. I tryed to connect an old Snap-on MT2500 with the 20 pin connector adapter to my diagnistic port and the scanned could not estalibished connecting. However, I read here that some succeeded on using this scanner with OBD1 24v. I checked the connection of my 20 pin diag connector and everything is correctly wired to the DME. I only have 8.25V on the RXD pin 15 when I should have 12v. On the TXD pin 20 I have 0 volt... I don't know if this is normal.
I'm kind of stuck because up to now I can't see nothing with the scanner. I'm not sure on which component should I replace and I'm not even convince that my AEM AFR gauge is giving me proper numbers. I may have an opportunity to try another ARF gauge (innovate). Note that the vanos as been adjusted to kick in at 4000rpm, and the fuel is not perfect at that spot. I can hear knock and I see the AFR quickly bounce over 14. This tends to make me think that my wide band is OK.
So any help on the possible cause and on how to plug a scanner to my DME would be highy appreciated!
Thanks a lot!
Last monday, got the car retuned on the dyno due to the freshly rebuilt engine. Got about 1500 miles on it before getting it tuned. The car was pulling nice numbers on the dyno. Right after the dyno tuning session, on street runs, it was showing about 12.5 to 12.8 AFR on WOT pulls which is correct. After this, I let the car for about 15 minutes and now on WOT pull it was showing Around 14 AFR! the engine and intake were kind of very hot when touching it. We let the car cool down for about an hour to let the intake and everything cool down. I got out on the highway and got nice 12.8 AFR WOT pulls. I again let the car sat for 15 min and went again on the street. I got 14 AFR on WOT again!
Other than that the car runs great. THere is no knocking sound when the AFR is leaner but I'm pretty sure I can feel a drop in power.
The AEM AFR Gauge are autocalibrating and I leave the cycle complete when turning ignition on before starting.
One thing to note is that the fuel tank purge valve is not hooked up. The tank is presently vented to atmosphere right after the charcoal canister, the purge valve is still there and the TB nipple is capped. (My fuel tank was pressirizing itself on hot track days)
The tuner told me that it could be the Engine coolant sensor, the IAT sensor or the MAF that is providing the DME Erratic data. He said that I should check the data with a scanner before replacing any parts, and I'm also thinking the same. I tryed to connect an old Snap-on MT2500 with the 20 pin connector adapter to my diagnistic port and the scanned could not estalibished connecting. However, I read here that some succeeded on using this scanner with OBD1 24v. I checked the connection of my 20 pin diag connector and everything is correctly wired to the DME. I only have 8.25V on the RXD pin 15 when I should have 12v. On the TXD pin 20 I have 0 volt... I don't know if this is normal.
I'm kind of stuck because up to now I can't see nothing with the scanner. I'm not sure on which component should I replace and I'm not even convince that my AEM AFR gauge is giving me proper numbers. I may have an opportunity to try another ARF gauge (innovate). Note that the vanos as been adjusted to kick in at 4000rpm, and the fuel is not perfect at that spot. I can hear knock and I see the AFR quickly bounce over 14. This tends to make me think that my wide band is OK.
So any help on the possible cause and on how to plug a scanner to my DME would be highy appreciated!
Thanks a lot!
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