[85lebaront2]

This is using a 1991 SBEC with a modified calibration. I just finally got the SBED to work correctly as far as "waking up" on input from the distributor HEPs. I went ahead an put some ethanol free premium gas in the tank, ran a jumper from the bulkhead connector to the left side body harness to run the fuel pump.

Using a spare turbo distributor, with the key on, got fuel pump activation, and immediately found a bad O-ring on the pressure regulator. Fixed that, and tried again. The fuel rail and injectors are not installed in the intake as I am using the 1987 2 piece intake. This time I did get a beautiful cone shaped pattern from all 4 injectors, but rather than triggering sequentially as the SBEC is supposed to, they were either bank firing, or all at once. They seemed to be firing as a batch fire, all 4 at the same time.

My question is, does the SBEC have a basic "fail safe" limp mode if the sync HEP is bad and fire all 4 injectors simultaneously as part of that strategy. The reason I am asking, is I know Ford did on their DIS V6 engines so it wouldn't leave you stranded if the cam sensor failed, they would revert to a bank fired mode.

I do not have the dash installed, so do not have the MIL available for the "key dance". After this current batch of nasty, very cold weather I can repeat everything with my Snap-On Solus Pro and see if it shows any HEP related codes. I know I will get an O2, air temp and knock sensor codes since with the upper plenum off and the fuel rail off the lower, those are not connected.

 

[Bob Lincoln]

No, if the HEP signal is bad, you get nothing - just cranks. No failsafe.

 

[AC TC]

It doesent have a cranksensor?
- without it its difficult to time the Engine and perhaps the calculations for injector timing is sensitive to crankposition and not only the dist.

 

[GLHS60]

HEP performs both crank and cam sensor functions

Young guys!! LOL

Thanks
Randy

 

[ImperialCrown]

The lower shaft vane provides the #1 TDC location for the PCM. The upper 4 vanes provide the spark plug firing trigger.
There is no injector limp-in strategy. There is sequential and multi-point injection plans. I would have to look at the 1991 2.2L turbo driveability tests book again to refresh my memory on these. I have one in the attic.
They may all mist at key-on when cold for a start prime? I found this image, but it may not be the correct distributor:

0900c152802514e2.gif

 

[85lebaront2]

IC, that is it, the vanes are all in the bottom, but one of them has a hole in it on the turbo distributor giving a 3 long, 2 short pulses per revolution at each of the HEPs. There is no mist at key on, just ASD and fan relay "pulse". I have the turbo II diagnostic manual, but do not have the 1991 driveability manual. The LM/PM and SMEC used a multi point (bank fired, 1.2 and 3,4) plan, the SBEC is supposed to use a sequential injection plan. That was my main reason for going to the SBEC. My original had the LM/PM from a 1987 Daytona and a MOPAR performance calibration on the socketed LM.

If I can get this issue resolved, I can reassemble the intake and start the engine. Once this extreme cold departs (Wednesday hopefully) I am going to connect all the sensors except the knock sensor, but may be able to get it hooked up and see what happens then. At least I now have a seemingly properly working SBEC.

 

[ImperialCrown]

Are the injectors being grounded individually at the SBEC? Each injector has a return wire? This would allow sequential firing.
I can dig out the 1991 turbo drive book if it would help. I may even have an extra copy.

 

[85lebaront2]

Yes, they are grounded by the SBEC. Injector return wires are individual to pins K11 - K14 of the SBEC. If you get a chance to dig it out that might be a help. The friend who sent me the calibrated chip, feels it may be a limp mode, he has a simulator he has built for testing an SBEC and for verification of function on modified calibrations.

Once we emerge from our "deep freeze", probably tomorrow, I am going to try first connecting all the sensors and use the spare distributor again and then, with the fuel rail still out, try using the starter to spin the engine and see if that gives me a sequential spray.

If I can get a good solid behavior from the injectors, I will finally, after nearly 10 years get the engine fired up. This will make the car mobile under it's own power.

 

[85lebaront2]

Ok, temperature got up to around 57° F today so I tried using the starter to turn it over. The injectors are all 4 firing together, pulsing so they are obviously not grounded. Tomorrow I can see if my little hand held scope can see the signals from the two HEPs while cranking it (plugs aren't in right now) I will have to pull the fuel rail back off so I can watch the injectors.

 

[Bob Lincoln]

I have a small handheld scope and am able to capture my injector signals from my 84 Daytona Turbo Z.

 

[85lebaront2]

Two things, here is what I have, and the short test harnesses I made up. The second, I tried unplugging the Sync pickup and got no injector pulse of any kind. I didn't go into looking at the HEP patterns after that, as it seemed academic. I did find one of the injectors is leaking, so it looks like I need to find a good source for them.

I guess my next evolution, if and when it gets warm enough again, will be to disconnect the fuel pump power and with the ASD jumpered and the SBEC out, probe pins K11 - K14 to ground and see if one or all four injectors activate. If one each time, then the problem is the SBEC, if all four than I have to dig back into the wiring harness (loads of fun).

 

[Bob Lincoln]

Two things, here is what I have, and the short test harnesses I made up. The second, I tried unplugging the Sync pickup and got no injector pulse of any kind. I didn't go into looking at the HEP patterns after that, as it seemed academic. I did find one of the injectors is leaking, so it looks like I need to find a good source for them.

You won't see any pulses on the upstream end of the sync connector, because they are generated *downstream* by the Hall effect sensor. The connector supplies 8V and ground, I believe, and carries the signal from the distributor back to the computer. So if you look at the distributor end of the connector while unplugged, you see nothing on any of the 3 wires. If you look on the upstream end, you see 8Vdc, and ground, and nothing on the signal line.
You need to look at the injector pulse, which is the ground of each injector (since the low-side is the switched side).

 

[85lebaront2]

There is a signal from the HEPs, it is 3 long pulses and 2 short pulses due to the "window" in one vane. It is essentially a negative signal (pulled to ground). The injector pulses are probably only going to show pretty well identical on any pair, rather than the desired 180° crank degrees between 1 - 3, 3 - 4, 4 - 2 and 2 - 1. The test harnesses I made have the harness socket for the HEP and three 0.125" Ford Wedge-lock pins as they are the same diameter as the HEP connector pins and three test leads with the stripped ends tinned so they will not oxidize or get damaged easily, they are to be inserted between the HEP plug and harness socket of each allowing verification of 8Vdc, signal ground and HEP output.

The reason I plan to first check the injector circuits by grounding the K11 - K14 circuits at the SBEC connector (SBEC removed) is to determine if I have a wiring problem or it is completely SBEC related.

 

[85lebaront2]

Ok, got a bit warmer than predicted today. ASD jumpered, no SBEC connected. K11, K12 solid to chassis/battery ground. K13, fires injector #4, K14 fires injector #3, K15 fires injector #2, K16 fires injector #1. This verifies the harness wiring is correct from injector plug to the SBEC 60 pin plug. Therefore, problem must be in the SBEC.

 

[David Eidell]

I have a 4-channel Tektronix color scope on the bench. It cost more than my life insurance payout.
Does such a thing as a bargain-basement priced scope meter exist?

 

[ImperialCrown]

I have a couple of old vacuum tube scopes in the shop, a military one and a Heathkit 5". I rarely need to see anything over 30 MHz.
There are handheld and pocket scopes for around $100:
https://www.newark.com/seeed-studio/72-12875/dso-nano-v3-pocket-oscilloscope/dp/68Y0128
https://www.newark.com/velleman-sa/hps140i/product-range/dp/92T1662
They are a useful diagnostic tool when seeing a waveform would help answer a question. Used scopes from someone who is upgrading can be a good buy as well.

 

[85lebaront2]

I have a 4-channel Tektronix color scope on the bench. It cost more than my life insurance payout.
Does such a thing as a bargain-basement priced scope meter exist?

Maybe, now that solid state stuff has come way down. You have the Rolls-Royce of scopes, one I would have loved to been able to afford. The EXTECH was bought from Grainger through a friend who was able to get two of them (one for each of us) using his NASA discount. It is Korean built and so far has worked quite well for me. Between that, my Snap-On Solus Pro and the MAC ignition scope I can check most systems. The mac will do some DIS, COP is pretty will a substitution deal.

 

[85lebaront2]

Received a used SBEC yesterday from Arizona parts, connected it and did my injector test, nice little sequential squirts from the new GP-Sorenson injectors. I went and reinstalled them and reassembled the intake (upper plenum is a royal pain to get all 8 bolts installed and tightened) and put the plugs back in. Took a little bit the first time, and bam, first time in roughly 10 years it fired off.

Now I need to finish sorting out the cluster of vacuum lines on the back side of the valve cover and fill and purge the cooling system so I can run it long enough to get it fully warmed up.

 

[85lebaront2]

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