gm efi conversion for a mopar 2.2?

[Ivan Blackford]

thanks for all the info...hopefully i can shed some light on my
situation....

the van in question is an 85 dodge mini ram van (same as caravan, but no
seats...)

the 2.2 is carb, but it isn't feedback. the plan is to take an exhaust
manifold from a tbi 2.2 and bolt it on to the head. that would give me an O2
sensor. next, I will take and put either a tbi manifold (for a tbi
conversion) or a turbo manifold for a mpfi conversion. The turbo setup uses
the same head as the carb and tbi..(minor water jacket differences from what
I've researched), so the head _shouldn't_  need any reworking to make it
work. The knock sensor is something I'd have to figure out...the turbo has
it, but of course I don't have a turbo block. A map/maf sensor wouldn't be a
problem...it's something I could easily find a way to work it in. The fuel
pump is a mechanical type, so it would have to go for sure. I could easily
swap in a later gas tank with an in-tank pump, that would probably be my
best option. I guess my biggest concern would be getting the signal from the
distributor to play nicely with a gm ecm. I don't know how i'd be able to
that...maybe there are specific ecm's that will work better than others. Any
advice on this would be greatly appreciated...

Thanks.
Ivan Blackford
itech at lks.net
----- Original Message -----
From: "Volker" <Volker at VWSoft.com>
To: "Ivan Blackford" <itech at lks.net>
Sent: Sunday, September 02, 2001 3:47 PM
Subject: gm efi conversion for a mopar 2.2?


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> Hi Ivan!
>
> I've seen your message at DIY GM EFI. Well sounds very interesting
> what you're going to do but I don't think this will be an easy job.
>
> IMHO you cannot expect a carb to TPI / MPFI conversion to be possible
> at all for a DIY as (as I think) you would have to make difficult and
> lots of changes to the cylinder head. But I do think a carb to TBI
> conversion will be a possible job. This should not be too easy but
> possible (as a very simple picture you'll remove the carb and put a
> TBI unit on top instead).
>
> The only problems I'm seeing are:
>
> - - there's no ECM you may just plug in and have it playing the right
> game (software changes ARE required)
> - - the ECM is relying on different sensors (TPS, MAP/MAF, knock, CTS,
> O2) and is controlling different units (injectors, ESC/+HEI, IAC);
> these sensors and units are not already attached to your engine and so
> the job becomes difficult
> - - your fuel pump might be unusable for that job, too
>
> ECM software:
>
> The software is especially written for specific engines and injectors
> (flow rates). If you're using the wrong software (firmware on PROM)
> and/or wrong calibration (also on [EE]PROM) you might experience
> running too lean or too rich or might get a not well running engine
> (too less power under some circumstances). The the ECM software will
> be a BIG issue!!!
>
> Unfortunately as being a computer software developer I might not be of
> any help to you as I'm just at the very, very early beginning of the
> learning curve with EFI software and have too less knowledge.
>
> ECM sensors:
> - - TPS: this one is attached (three wire connector) at the TBI unit -
> so no problem
> - - IAC: at the TBI unit (4 wire connector) - also not a problem
> - - knock sensor / ESC: not installed at carb'ed engines - this has to
> be installed
> - - HEI: not installed at carb'ed engines - to be installed (connected
> with ECM and EST)
> - - MAF / MAP: not installed at carb'ed engines - see comment **
> - - O2: not installed at most carb'ed engines - see comment ***
>
> comment **
> The MAF / MAP sensor is being used by the ECM to detect the intake
> flow. It (either of both) is being used to calculate the Air/Fuel
> ratio / injector pulse timing. A normal ECM controlled engine should
> work with a dead MAP / MAF sensor and work at a basic calculation (by
> only trusting at the TPS sensor for calculation) but I don't think one
> should rely on a ECM working without MAP / MAF at all. I've checked my
> car with a disconnected MAP sensor connection and the ECM commanded
> the engine to run at high idle but the engine stopped a few seconds
> later - so I don't know if you might run without one (I suggest to use
> one, some folks swear on MAF but a MAP sensor will also be fine). The
> vacuum connection to the MAP sensor should go to the TBI unit at most
> systems (so no changes at the engine should be required).
>
> comment ***
> The O2 sensor is being used by the ECM to "see" how good the air/fuel
> ratio is being calculated and high good or bad it's being burned - the
> O2 signal plays an important role for the ECMs' calculations. On the
> other side it's really only used for cars equipped with a catalysator
> (I suspect your car doesn't have one - am I wrong?). Even if your car
> doesn't have one I would suggest to install an O2 sensor (this might
> be worth a discussion).
>
> As you'll follow my suggestion for a TBI unit, you should look at one
> that has been used at a similar engine. I've got a GM EFI workshop
> manual (print date 1986) that lists the following engines:
>
> 2.0L L4 (VIN P, RPO LQ5): Chevrolet, Pontiac, Olds, Buick, Cadillac
> 2.5L L4 (VIN R, RPO LR8): Chevi, Pontiac, Olds, Buick
> 2.5L L4 (VIN 2, RPO LQ9): Chevi, Pontiac
> 2.5L L4 (VIN U, RPO L68): Pontiac, Olds, Buick
> 2.5L L4 (VIN E, RPO LN8): Cevi S-10
>
> The 2.0L engine is using a model 300 TBI unit and the 2.5L engines are
> using a model 500 TBI unit (both are single injector driven units).
>
> The GM manual states for the model 500 unit: "Same as model 300 except
> banjo fitting used in place of fuel inlet nut" (whatever this means).
>
> There should be other engines with fitting TBI units as the GM manual
> is a little bit "out of date".
>
> When doing your job I guess you'll run into the problem of connecting
> all the sensors as the connectors are hard to get.
>
> I hope all this will help you a bit.....
>
> Volker
>
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