Thom

I am beginning to think the lean spike is something that will always be there, at least to a relative extent, when using the Bosch Motronic.

Here are some logs done this morning.
Curiously, the second pic doesn't show the spike!

PS : as you can see the VR boost solenoid and a dual BB turbo make a happy pairing - 16psi at 2700rpm!

fast951

A bit OT.

Thom, What changed between the first run (with a spike) and second run with no spike? Do we assume the followings are the same: Software, MAF, PB, Turbo, Injectors, Air filter?

Can you take a snapshot with the slider bar showing when you started applying throttle and when you reached full throttle.

The only thing I see different is the first graph shows you were at PT and already on boost vs. the second graph you were at much less throttle and no boost. I would experiment to see if the throttle position and the base vacuum/boost affect the spike vs. no spike.

fast951

I know it's impossible to tell after so long, bit I'll ask anyway. What did change to make the issue go away. Did any of the followings change after the engine build: DME, KLR, MAF, Injectors, FPR, Fuel Rail, BOV, Software, PB, TPS, Turbo,.. ?

JarmoL

Can this be done with Motronic? I have mostly similar MAF setup as Thom has and I have the same lean spike also.

fast951

Yes the Motronic has acceleration enrichment. Your setup and Thom's are different. Aren't you using a mafterburner?

333pg333

You know John, it was so long ago. I'd have to sort of go over it with Sean and try and remember what or if we changed anything between builds. Actually remembering which build might be a bit taxing on the old grey matter. I do remember we tried a different DME which initially I thought had cured it, but it did re appear. Also my issue wasn't happening often enough to be able to easily test it so that made it more difficult. Everything else would have stayed the same I believe.
From memory it was at WOT around 4500rpm and as if there was a complete cut in everything momentarily. We did capture it on the dyno once but I didn't have any data logging equipment at that time.

JarmoL

Yes, I have Mafterburner installed. I have run the car with Mafterburner removed though and it was still the same. Some more troubleshooting is obviously needed.

fast951

FYI the Mafterburner is not compatible nor is recommended with your setup. This may be a different issue all together, just wanted to mention it.

A.Wayne

Appears to be in the TP circuit .....

V-flex didn't you have a standalone system ? what happened ? ......

333pg333

Different motor, different car. Only just getting the car with the V Flex going so can't post any results but I'm confidant it will be good. Using it this coming weekend at the first track day of our season.

fast951

Patrick, your dyno chart above looks as if the dyno RPM pickup was losing signal or there was a ignition shut off.

333pg333

That was the 'Glitch' I was experiencing which just so happened when we were on the dyno John. So not the dyno. I think you're right in surmising total ign cut. That it didn't happen with any pattern made it more difficult to solve. As it turned out the motor failure sorted it out because when the next one went in, the problem wasn't there. Perhaps a connection issue somewhere?

Thom

Nothing!
There are 31 seconds between both pics.

Will do.

Yes, but the curious thing is that older logs tend to suggest the opposite: the less vacuum before I apply full throttle, the less pronounced the lean spike.
Latest mods, before this last run above was done, are a new ignition coil and Denso IW22 spark plugs in place of the Bosch WR6DC.

Is there a way to identify a fault in the TPS wiring loom?
Since I log the TPS signal with the Zeitronix, I assume the logs would have shown a faulty sensor and/or wiring loom already?

fast951

Based on both logs from above, I see the vacuum/boost & TPS as the only difference. Just something to explore, it may or may not lead us to pin point the real issue. The goal is to narrow it down to a few variables.

Based on the log, I do not suspect a bad TPS or wiring.. However the state of the TPS (Idle, PT,..) may be of value in determining the root cause.

Any chance you are getting a misfire? If a cylinder is not firing, it'll dump the raw fuel out and it could show up as a lean spike.

Logging the MAF signal will help as well as it affects the AFRs.

Todd951968

This car has a Haltech E-6 computer. Haltech is apparently not supporting this earlier version. I think all I need is the cable that connects the computer to a laptop. The laptop has a standard connection but the on off the car has a 3-hole connector. (See photos) I don't think I can get the necessary cable off the shelf at BestBuy.

Does anyone know how I could get one?