FI Problems/considering Weber Options

[Chuckster]

I have been a long time lurker at Rennlist but there is very little discussion on teeners. I think I have found a home for 914 discussion. I would like to thank Geoff for turning me on to your BBS.

This a 914 2L that I hope to use for ITA. The engine is stock and needs to remain stock to keep me legal for SCCA. I realize Webers are technically not legal.

I posted on Rennlist a discussion on switching to Webers. I will just re-post here my FI problems:

The car is leaning out at higher RPMS. I have changed the FI harness, computer, new TPS, put in new injectors. Have put in a known good atmosphere meter. The head temp sensor is on variable resistor so I can fine tune the air-fuel mixture. I have disconnected this and inserted a resistor substitution box. At idle and the resistor box set at say 200ohms the car runs fine. Under heavy load the car begins to get leaning out popping and also begins to miss. When I put in high resistance (2000 ohms) the car runs very rich at idle and under load runs strong, no missing up to about 5000rpm.
5000rpm is my redline so I dont care if it misses at higher than 5000rpms.

I have had lots of help on all these diagnostic tricks including changing the trigger points checked the fuel pressure it is steady if a bit low (29.5psi) through heavy load.

I and others have torn this thing apart so many times, I cant remember if I have checked some simpler things such as the little injector rings at the head. This very well could be the problem. But honestly cant think of anything else to do or check.

I have access to a test carb. off of a '70 914 and will try that. If this fixes the problem, I will put the carbs on. Something my sister thought of which was a crimp in the fuel line. I suppose we could have good pressure and not enough volume.(?)

I do appreciate the input. Any thoughts or experiences would be great. Someone else mentioned the duel 40's. Which does seem to be the set-up.

Thanks again for the suggestions.

Chuckster

[Bleyseng]

Well for lean popping problems first look for vacuum leaks, everywhere! At decel the motor is pulling 15hg of vacuum so a leak could be it. Use starting fluid sparingly, spraying the injectors, plenum, hose connections, to find it.
As for leaning out a high rpms, is the MPS a 043 unit? IF it is try using a 037 MPS as they are set from the factory richer. Otherwise you have to adjust it which takes some special equipment (ie a Wavetek inductance meter) and a dyno.
If I remember right, the mix knob only is in effect when the tps is at idle. See Brad Anders site for more details on this.
WWW.members.Rennlist.com/PBanders
Geoff