So I replaced the 1.8L with a SCAT 2056 long block with a Web 73 cam and 42x38 valves. They provided 4 bolt (intake) heads so I could use the 1.8 tin and carry over L-Jet system. The CR is 8.5 and I have an adjustable FPR. The injectors are stock 1.8L L-Ject. I can dial in the idle AFR easily but I get rich 9.0 AFR on very light tip in. I also go lean at higher speeds (>4000). I suspect the static is set too high on the AFM. Any suggestions?

check out this link you may find it helpful.

http://www.914world.com/bbs2/index.php?sho...40434&st=20

Switch to Megasquirt, HalTec, AEM, SDS........... you're expecting a lot from a system designed when it was. Can it be cleaned up, sure, is it worth spending huge amounts of time, nope.

Issue is your testing ancient technology with Modren tools and expecting Modren near perfect out comes. To get that you need a processor and data maps beyond what transistors and diodes with resistor can provide.

Stephen,
I think with the L-Jet knobs at hand (fuel pressure, AFM static, AFM dynamic and CHT resistor adder if needed) I should be able to arrive at a safe calibration. Like 12.5-13.2 moderate load, maybe 12.0-12.5 WOT and 13.2-13.5 at idle. I think I will start with WOT calibration since that will determine my fuel pressure needed with the 1.8L injectors. Then I can adjust for moderate load and idle.

Best of luck and let us know where you land.

Go find 4 injectors for a Datsun/Nissan 208ZX, vintage 1980 or so. They are the same as the bosch injectors for a 912E, and work great with the L-Jet system. They are a complete bolt on, no mods needed. Make sure the intake has no vacuum leaks and verify the fuel pressure (28psi at idle with the vacuum hose hooked up) with a gauge. You just need it set to the stock pressure with the bigger injectors.

The 2056 won't kill the AFM from airflow, so you don't need to readjust the flap. Just use it as is. The cam will probably make it idle really poorly when cold, but once it is warmed up, it will run really well.


Let me know if I can be of any additional help.

Clay

Thanks for the advice. This will take some time with the other things going on.
Regards
Ray

Clay,
Wouldn't it make sense to also use a 912E (2.0L) L-Jet ECU on a 2056. It may have a better fuel map than the 1.8L ECU Have you heard if anyone has tried that or is it not required?
Ray

I have never tried it. It may be better, but the 912E ECU is hard to find.

When trying to get the old tired 1.8 to run I just jumped on the freeway while watching the gauge under load then at cruise.
I would get off the freeway and adjust the spring pressure then hop back on the freeway.
I kept doing it until the numbers looked acceptable.
In my case it was dumping too much fuel so I tightened the spring.

Good plan. I have some FJ707 injectors on order which are replacements for 2.0 912 with L-Jet. I also have a fuel pressure regulator coming which is supposed to be for a 1.8 914 which should be 35 psi. All of the other FPR's I purchased are 40-42 psi. I will install the correct parts and give it a try.

Clay,
I installed the FJ707 General injectors and the Beck Arnley 158-0073 FPR both of which reference a 2.0L 912 engine. Engine off pushing the fuel flap I get 41 psi on the gauge. It shows about 34 psi gauge at idle with the vacuum compensation. After a good warm up run I adjusted the AFM to get 13.5 at idle and about 12- 12.5 at WOT. My RPM limit is 4000 RPM unlit after break in. The throttle body is a 45mm bus unit. The bad news is that I get 8.5 to 10.5 AFR at part throttle tip in with some rich misfire. Heavy crowd is 13-13.5. If I tighten the AFM then I get 15-18 AFR at idle---no good. I think the fuel pressure is too high but this is about the third FPR that I have tried. Another issue is that I cannot get the idle below 1200 even with the TB screw all the way in. (need to see if there is a hole in the plate.) I looked for leaks and even plugged the air bypass hose. I used rubber cement on the runner hose sleeves and Permatex on the intake gaskets. Timing is set at 7 degrees with the vacuum hose off. Any suggestions would be appreciated.
Regards,
Ray

we have never had any luck with using anything but the stock fuel injected cam with fuel injection. Now that you have built the engine, the only alternative is to change to megasquirt as previously stated, carbs, or change the camshaft

Have you checked the condition of your potentiometer. Partial throttle going lien tells me it is not adding additional fuel so the question is why. The flap could be sticky or the potentiometer is not giving a good signal at partial throttle. Lean at idle should not be that bad. I have read about guys trying to get above 15 on the freeway. Heat becomes a problem when lean but unless you’re at idle for long periods of time I would not think that would be a problem.

It actually goes rich at part throttle. I just checked to AFM voltage output and it appears to be a smooth progression.

George,
I was given the impression earlier on that the Web 73 was not a carb cam and that it would work well on a 2056 and L-Jet. I really do not want to do carbs so I guess I will need to do the best I can with what I have. I'm trying to ignore that sinking feeling in my stomach. I'm sure you know what you are talking about.
Regards,
Ray

Close down your AFM bypass screw, it should Richen it up at idle then tighten your spring slightly to get your wide open throttle at the right point assuming your fifth injector is working properly.

I will try again next week. I need to demo a kitchen at the cottage this weekend.

The fuel pressure is a little high. What fuel pump are you using?

Also, you might want to try an AFM that has not been opened up. And also replace the gaskets in the oil filler cap. If they are bad,they will cause a false air issue, and make the car run bad. If someone that didn't know any better changed the AFM to compensate for the bad oil cap seals, you can get all kinds of screwy mixtures.

Clay

double post,sorry.

keep it all stock and don't add lots of changes till you get to a point where you don't know what is working or not.
Stock injectors and afm will flow to what ever displacement change is made,increased fuel pressure has no effect and is not required ,an adjustable FPR will sort that.
I don't know about the cam you have and how it works with your big valve heads you have with the L-jet,if the AFM wiper is bouncing around @ idle there is little you can do ,can indicate poor vacuum signal ,but do check for air leaks as this system has no tolerance for them.
Good luck.

Clay,
You were correct when asking about the fuel pump I am using. It turns out I installed a (cheap) MostPlus pump but turns out it is 5 Bar and 300 l/min as opposed to the correct one which is 2.5 Bar and about 167 l/min. I have ordered the correct Bosch replacement pump. I suspect that the MostPlus pump was swamping the bypass mechanism in the regulator. If there was no more range of authority in the regulator then at higher manifold vacuum like a light tip in the regulator cannot compensate for the vacuum which would cause excessive fuel flow at high manifold vacuum. Hence the 8.5 to 9.0 AFR on tip in. More to follow.

You can get a pump that has the same volume and pressure as a stock 914 FI pump at FLAPS. It is an Airtex E8445 or equivalent. About $100.00, and available locally. One in, one out. We have run the same pump on Betty's L-Jet system for years with absolutely no issues.

Good luck!

So I replaced the fuel pump with the correct spec and that brought the fuel pressure in line. I still had the rich (8-9 AFR) excursion at cruise / light tip in with rich misfire. I was running good 1.8L injectors so the only part left to suspect was the AFM which was supposedly "rebuilt". Upon inspection and disassembly I found some oxidized soldered connections on the alumina substrate. Fortunately I had a spare board and after the swap the AFR was back to normal and the engine ran and sounded great. I had been chasing injectors and fuel pressure for months but it turned out to be a bad AFM. See pictures below:

As found substrate
Click to view attachment

Replaced substrate
Click to view attachment

Congratulations

Thanks. I received good advice from Clay and others.