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MG MGB GT V8 Factory Originals Technical - Help for Flapper Valve Fuel Injection

Hi Guys,

I'm at the late stages of converting mt Buick/Rover V8 to 1980 Rover SD1/TR8 Injection and am having some problems. Here are the symptoms.

1) Big backfire through the plenum

2) Motor does not fire, yet timing is correct, and fuel is being delivered to the fuel rail.

3) Connections to the combo relay are unclear.


The Injection system is from a 1980 SD1.

Any ideas for me guys?

Thanks,

David
David Cousins

Hmmm, backfiring indicates you have at least some spark and fuel. I had a similar result fuel injecting my B once. Turned out the distributor worked it's way out of the the block - I had set the timing a few times and the distributor clamp became too bent to do the job.

Just based on that, I'd experiement with the timing a bit more. Even though you think it's right, 8 cylinders of ignition wiring creates a lot of chance for error.

regards,
Mike
Mike

Mike,

Thanks , I have checked and rechecked the timing and it is fine, but still no lift off. Any other ideas?

David
David Cousins

Well if you're sure your spark is strong, you probably should check fuel pressure and make sure it's correct for the application. I know Bosch CIS systems of the same era use slots for fuel control and have about 40lbs of pressure. What kind of pump and fuel pressure regulator are you using? Have you hooked up a fuel pressure gauge?

Mike
Mike

Mike,

I'm using the Bosch high pressure pump as used on Injected Triumphs/Rovers and many assorted cars of thr eighties, and the Injection system is L-jetronic licenced by Lucas. I have not put a fuel pressure gaude on the system to check it . Will try that next.
David

Stupid suggestion.....is your timing out by 180 degrees?
Regards
Tony
Tony Bates

Tony,

I'll check it again, but I do believe it is timed correctly. I always knew this was going to be the fun part.

David
David Cousins

Tony,

All the timing issues have been resolved and the car now fires up but does not stay running. Possible factors are Exhaust not installed, electrical disconnect/miscue or fuel delivery or combinations of any or all factors. I'm trying daily to figure it out and keep it running for more than a few seconds. Any more ideas given my feature set?

Thanks,

David
David Cousins

Afraid I can't help directly as I have my own problems with a Holley..... however, take a look at www.v-8.org.uk. Helpful bunch who know just about everything there is to know about all the different types of injection systems fitted to SD1s etc.
Nick Bentley

i know little about the flapper set up but here are some things to try.
Your distributor is sparking OK, and hopefully your spark plug leads are all leading to the right sparks (personal experience speaking here!)so thats one important thing accomplished and it sounds like you've got the fuel supply working so that's two causes for a congradulatory drink!.
It it starts every time, but doesn't run that that implies that the computer is not getting the right signals.
Possibilities;
The throttle sender is not sending. Does working the throttle extend the running time. If not, then thats a likely culprit.
the temperature senders have been swapped over so the computer thinks the water temperature is the fuel temperature and VV. Lots of people do that one.
Your flapper is not sending the right signals. If the engine backfired through the air intake thats a possiblility.
I don't know anything about the idle set up.
Good luck with it, just keep knocking over the possiblilities one at a time and you'll get there sooner or later.
Peter

I wouldn't run it very much without the exhaust system installed. If you do, the hot exhaust valves could be cooled too quickly when you shut down and be warped.
Edd Weninger

When I first installed my hot wire system, I could get it to start, but it would not run. Through the wisdom of this forum, I got it to run by chasing down a couple of vacuum leaks. Check everything that connects to the plenum to see that it is sealed.

Jim Stuart

Thanks for the new leads, which I'll now chase down diligently. I was too late to attend the V8 meet in Townsend but there is still a lot of summer left, here in Northern California and I would love to enjoy some of the nice weather top down.

Will let you guys know how i get along.

Thanks,

David
David Cousins

Edd, If I may I would like to use your example for a bit of theory. Maybe others would like to chime in and bring about their theories. Anyway I hope they do.

This reminds me of the "don't leave a car battery sitting on the concrete floor because it will discharge" bit. Aother one was the 100 MPG carburetor. What's the battery doing on the floor anyway? Was it removed because it was under suspicion of having a problem? This has never happened to me and I leave 'em on the floor just for the 'ell of it. Never had one to discharge that was known to be good.


I've heard about the warped valve syndrome for years but never been a witness to the situation, known of anyone that it ever happened to, or done it myself by using an open header or bare exhaust ports. I might believe it could be possible under certain circumstances on the old flat head engine types but with the newer fuel injection engines I will have to say it couldn't happen under normal circumstances. I believe this because the engine would disperse it's heat out of the cylinders, via the intake valves via the intake plenum and through the butterfly in the TB which would bleed trough very slowly because it would be closed. Thus, a rushing backdraft across an exhaust valve couldn't happen. If both intake and exhaust valves were open on a particular cylinder the butterfly would not let the heated air escape anyway because of the collected hot air in the plenum. If the heated air tried to escape through another open intake valve the action would be compromised by the heated air coming from it's own cylinder. If the engine dispersed the heat through the exhaust valve upon engine cool down the heated air would slowly bring the valve back to the surrounding ambient temperature because of the pressure of the moving warm air past the valve and no damage could result.

It's never a good idea to leave intake or exhaust ports open to varmints, critters or bugs. They might be chewed up in the starting and running process but if a mouse was carrying a switch blade in order to defend himself from a good sized roach, the knife could cause some damage in the engine.
Dann Wade

Hi Again Guys,


In the continuing saga of getting the engine to run with the fuel injection system, I have a few more questions, which are as follows.

1) What does the extra air valve do ? Where on the plenum should it be connected? I'm using the system from a 1980 Rover SD1 Bosch/Lucas 4 CU ECU with Lambda Sensors.

2) Would Vacuum leaks prevent the engine from running if all other components are operating as they should?

3) What does the overrun valve do? How does it affect engine operation?

I've spent many hours today with the help of my mate Tony Bates and have gotten some success in that the engine fires and stays running for a few seconds longer than I've experienced by myself. We have not changed any settings or connections.

We tested all electrical connections , namely power to the ECU, power to the injectors, power to the injector resistors, and to the throttle potentiometer.

In conclusion it seems the regular injectors may not be firing. What next?

There is a four plug connector called the feedback monitor port which we've also tested for connectivity and that seems to be fine as well. What other purpose does this serve?

I know this is a long post but i'm at my wits end and yet it all seems so close to running, hence the questions.

Thanks to all who have responded before and have pointed me in the direction that i've reached so far. I'm sorry i missed Townsend and meeting all of you guys.

David
David Cousins

Hi Dann,

You've thought it through more than I. I was picturing the engine without the exhaust maniflods in place, which might or might not be the case. If the headers are in place and the down pipes installed, I agree there would be no problem. Indeed, many airplanes operate just this way without problems.

David, I can't really address the flapper system directly, but if some functions are similar to the hot-wire, consider the following:

In addition to power to the throttle potentiometer, it needs to be calibrated to the butterfly position.

I'm guessing by "extra air valve" you mean the stepper motor valve that adjusts the idle speed above the 'base idle speed' which is set by the butterfly position. Mine is mounted on the rear of the plenum. The motor is capable of running at base idle with this valve closed. There are various procedures for getting the valve closed electrically, but I generally just pinch off the hose to check. If this is leaking (I'm assuming you have it mounted on the plenum) the motor will not run (too lean from the large vacuum leak).

Do you know if it is dying rich or lean? If not, find out.

I'm not sure what you mean by the "regular injectors". AFAIK, there is only one injector for each cylinder. If the motor starts, they are most likely working OK.

Don't know what you mean by "overrun valve", I don't have one.

Google for Rover sites, I found useful info somewhere when I was tuning my system.

Good luck. Frustrating at first, but it will purr eventually.

Edd Weninger

Edd Weninger

Hi Guys,

Hooray, the engine now fires and idles. I changed the ECU and now it fires up first time. Now the fun begin, tuning and getting ready for the first drive.

Thanks to all who have helped with suggestions and made me reexamine what i was doing.

David
David Cousins

Hi guys,

It fires, runs and drives. Hooray . Now i have to ine tune it and put everything back together. Thanks to all of you who have offered advice and support.

David
David Cousins

David:

Sorry to chime in so late, but glad to hear you have the system up and running.
There is an incredible tech piece at the following location. It covers ECU repair and modification to Eurospec with improved WOT and Lambda control.

Pay attention to the area on cold solder joints in the ECU. I resoldered the cap and drive transistor connections and cured a bad hunting problem at low speed.


http://www.team.net/TR8/tr8cca/wedgelab/index.html

All the best, I'm fighting a couple of poorly firing injectors on a TR8 that is on the road for the first time in 15 years.

Kelvin.




KJ Dodd

This thread was discussed between 13/06/2006 and 24/07/2006

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