Possible Lean condition in L-jet motor - HELP, Fuel injection issues Options

[Cupomeat]

Ok, I am having the following problem on my 1.8l Ljet induction 914 motor.

First the basics;
1.9L (96mm big bore kit with KB pistons etc.)
8.4 to 1 CR
1.8 heads built out to 2.0l valve sizing, etc.
Stock fuel injection with adjustable FP regulator turned 15% higher than stock, currently(Pre-Lambda L-Jet, bummer)

Now, the symptoms;
Under normal acceleration, the car runs great and sounds fine, but under prolonged full throttle, the engine heat seems to go way up and pinging occurs. No pinging ever happens when I am rowing through the lower gears, but only seems to happen in 5th gear after prolonged Wide Open throttle (WOT).

So, my assumptions;
1. The car is going lean at prolonged WOT resulting in high head temps and pinging.
2. Ignition timing does not seem to play a role in this as I've played around with retarding the timing to decrease the pinging, but it never goes away at Prolonged WOT.

My plan;
1. Buy a WB Fuel/air ratio gauge and weld in the bung for the 02 sensor to support my theory

2. I have an inline fuel pressure gauge in the engine compartment, but can't watch it when I drive the car, especially in 5th gear at WOT (for very long, LOL)

3. Check to make sure the throttle switch is working to trigger WOT

4. If #3 is fine, is it possibly the fuel pump is running out of pressure?

5. I am also going to install a remote oil cooler to try to bring the heat down, but on a mild 1.9l, it seems excessive, especially as I probably have about 85 hp.

6.Probably install a cyl head temp gauge to try to pinpoint temps besides oil.

7In the end, if I have to pay for Dyno time to get to the bottom of this, I will but I'd rather not spend that yet.

Anything else people can think of? Any help/thoughts would be appreciated.

Eric

[Brando]

You can rule out #'s 1 and 2.

The fuel pump for L-Jet puts out more than enough pressure. Without a FPR on there it can go above 50psi easy.

TPS has 2 circuits... Open (throttle closed) and closed (throttle open). When closed the ECU meters fuel according to the AFS (under 3500 rpm) or fixed values (above 3500 rpm). When open the ECU runs on the idle circuit - for 76 version of L-Jet it cut fuel via the injectors on deceleration until a certain RPM (1500? 1800? 2000?) and then kick back in, saves fuel and provides quicker deceleration or something.

If you have a blockage that'll create a lean issue. Have you had the injectors cleaned? www.witchhunterperformance.com does it for fairly cheap.

#3: When diagnosing fuel delivery problems and you have no idea the last time your filter was changed --if ever-- it's probably a good time to change it and continue diagnosing. Clogged filter can greatly effect your fuel pressure.

#4 - What you're trying to diagnose and/or fix.

Another thing to check... Are you using points? They're only good until about 5000 RPMs and then you might experience "floating points". This will give you that rev-limiter effect. I've tried different brands and BOSCH is the only way to go for these. Get the better points with the foam block. Remember to lube the cam lobes of the distributor shaft with the special grease. If using the stock ignition system set the gap and dwell accordingly or the injection system will have issues as well and then you'll be confused if it's ignition or injection or both. Chasing gremlins that don't really exist.

I overcame the dwell/gap issue by switching to a Mallory Hyfire system with the better (solid state) tach/EFI adapter and adjusted the points to a smaller gap. It doesn't use the points to build up a charge in the coil so I have almost no gap and no floating points issues.