GMC fuel injection

[ggenovez]

Hi everyone.

I was wondering if anyone has used a GMC Fuel injection system to work with a VW air cooled engine with Turbo.

GM made millions of these systems and are easily adapted.

My concern is with the bosch distributor and retrofitting it with a HEI pickup coil. Any feedback on that?

Thanks everyone.

[miniman82]

If you mean the old OBD systems that had to be programmed by replacing the MEMCAL, it's been done hundreds of times on other vehicles. No reason if wouldn't work on a VW, but with the low cost FI systems out there these days I question the need unless it's just a retro/special interest thing.

[ggenovez]

Thanks Doc,

Yes, I was referring to the old ODB 1 type and swapping the memcal.

A system like that would be in the $100 ball park.

What other system are out there that would handle the boost pressure and are relatively inexpensive?

Also if I did go this route what would recommend to give reference to the ECM

[miniman82]

OBD can be more expensive than Megasquirt, if you start out with nothing and have to buy the prom burner/emulator and all that stuff. I think at the end of the day MS is really your best option, because you can tune it as many times as you want with only a USB>serial adaptor and a laptop.

[ggenovez]

Thanks Miniman,

Fortunately/unfortunately I'm already equipped with the burning software/hardware. my 90 suburban gets 20MPG.

Hence wanting to go with something I already know.

[miniman82]

That's cool, I'm going through the same motions with my '89 Dodge Spirit at the moment but my burner crapped out on me. It's fixed now, but I'm waiting to get it in the mail so I can get back to work on it. It's a turbo 2.5, so I needed to edit the cal to go beyond the factory 11psi shutdown mode.

If you have everything, all you should really have to do is tell the ECU you're running a 3 bar MAP sensor and edit the fuel and timing tables to suit. Also knowing it was a 4-cylinder vice 8 might be helpful, or using an OBD ECU from a suitable doner car would prove to be easier. Just make sure you are able to index the distributor properly, or you'll crossfire under boost because of the timing retard involved. I think they actually made a GM distributor conversion, you might have to do some searching to find it.

If everything else fails, you might try the Ford stuff. I do believe EEC IV has some ability to be tuned, and you could gain a coil pack and distributorless ignition in the process. That alone makes a huge difference in the way the engine runs.

[ggenovez]

Any advice for indexing the distributor? factory came with a bosch 009

[miniman82]

It's possible to retrofit the reluctor pickup from another distributor into an OO9, so it might not be a huge deal at all. I took apart a Jimmy V6 reluctor and put it in a Corvair distributor once, you just have to be careful lining everything up so nothing hits. The other way requires more extensive machine work, because you have to turn down the GMC distributor parts so they will fit in a VW case. After that getting lined up and timed is the same as if you were still carb'd. Main problem is if you run a huge amount of vac advance the rotor can possibly fire to the wrong cylinder, so it helps to have a rotor with a wide tip on it. Or just go distributorless...

I still say the easy thing to do would be grabbing an ECU and ignition parts from a later model vehicle, more options and the programming was much better. OBDII isn't necessarily tougher to tune than OBD, but you do have to fiddle with turning off most of the emissions related crap so it doesn't go into limp mode on you.

[ggenovez]

ok. What do you suggest?

[miniman82]

I suggest using a later ECU and a more modern crank triggered ignition, or Megasquirt. But if you're stuck with what you have, you may as well give it a shot. Worst case it doesn't work, and you end up getting something different from the junkyard. I have a buddy who's an early GM injection guru, you might try dropping him a line? Name is Ted Brown, he does a conversion system for Corvairs using OBD1 components. He can probably point you in the right direction, as I haven't tried to put a GM system on another engine- only tune it on the engine it's already on.

[email protected]

[raygreenwood]

Also if you go the older GM route....read that as pre-2000 parts. Do not use the wiring harness. GM's parts have always been pretty good.....however their wiring harness connector quality before 2000 when they finally went to AMP Ev-1 style dual cantilever connectors was horrible.

High rates of un-diagnosable, intermittant faults usually north of 60k, miles. Vibrational wear issues primarily.

Some volvos and Saabs from the late 80s to mid 90s era used GM connectivity and had the same issues.

Ford had much better connectivity. Theirs used AMP internal connectors with Unique Ford plug housing designs. No patent issues.
Ray

[ggenovez]

Thanks guys. I really appreciate all the info.

Ray, your avatar made me laugh. I didn't realize the Haynes had a Bf109 repair manual.

Ok, I know that everyone says go mega, I just find their price is extreme. It's $300 for the ECM. A GM ECM can be bought for $30-60 proms are $2-3 and burners are $15-30. That's 1/3 of the price. THen you still need injectors, throttlebody, lambda sensor....

Am I missing something?

Ray, what you would recommend for a ECM?

Doc. I reached out to Ted, and helped quite a bit. No real data on a distributor option but suggested that a Ford reloctor, pickup coil could work.

I saw someone use a ford escord setup on a VW bug, but it was not under boost. Any other options?

[miniman82]

I know that everyone says go mega, I just find their price is extreme. It's $300 for the ECM

If you don't shop it is, I paid $175 for mine from this guy many moons ago (price lower now @ $140):

http://www.glensgarage.com/catalog/mega ... -p-29.html

If you're using high-Z injectors you're done, if low-Z you also need the PWM board ($58):

http://www.glensgarage.com/catalog/peak ... p-134.html

These are kits, so you put them together with instructions in the manual. Of course the price goes up if you get one assembled, but you shouldn't be surprized by that. If you do some shopping, one may come up in the classifieds or on Ebay from time to time. No reason I can see spending $300 on an MS computer. IMO the not having to mess with PROMS thing makes the extra spending worthwhile in the long run, and the adaptability for all types of different ignitions opens many more doors than just running GM hardware. But do what suits you, if it works who am I to argue?

[ggenovez]

Thx Doc. I'll dig into that

[Piledriver]

Last I checked glensgarage was not an authorized MS distributor anymore due to non-shipping after taking-money shenanigans.
Check on the msextra vendors page, he may have cleaned up his act.

I have personally had good customer service from Glen, but situations change.

A basic v3.0 mainboard ms1 kit is ~$200ish anywhere.

I suggest buying it up front with a ms3 case, instead of the std case, as it allows many upgrade options and only costs a few$ more, vs $~45 by itself.

MS1 will run your engine, but ms2/3 are far more capable and far more user friendly, have various handy test/diagnostic functions to test outputs etc.

The later GM ODB2 stuff looks like its well covered by aftermarket software tools, and is immensely more capable from the factory. If you go there, please start a thread and document it for others, we are all curious.