Found a very interesting bit of info on a website here a work (GM). Another co-worker and Fiero owner told me about the site. It's run by the Service Parts Organization and is full of all kinds of info. You can get electronic access to Service manuals, Service bulletins, Service campaigns, diagnostic & repair proceedures, etc...

Anyway, I entered 1988 Pontiac Fiero into the search field and got a huge list of service bulletins and of course the campaign notices for engine fires! So I spent some time looking through some of the bulletins and found this interesting little bit of info
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INFO ON MULTEC FUEL INJECTORS DO NOT CLEAN MULTEC INJECTORS #91-6-111 - (02/15/1991)
SUBJECT: INFORMATION ON MULTEC FUEL INJECTORS/CLEANING

VEHICLES AFFECTED: 1986-1992 CARS AND TRUCKS WITH MULTEC TOP FEED INJECTOR APPLICATIONS

This bulletin has been written to inform technicians of possible damage to Multec injectors as a result of cleaning. The ball and seat design of the Multec injector eliminates the need of ever having to use an injector cleaner. By design, the fuel metering portions of the injector are not directly exposed to the intake manifold gases that are responsible for the build-up of deposits that can cause injectors to clog, as shown in Figure 1.

Some of these cleaners may contain high percentages of alcohol and other solvents that cause damage to the injectors' coil wire insulation. Damaged insulation results in low resistance or shorted injectors. Also, alcohol reduces fuel lubricity which increases friction at the injectors' critical bearing surfaces which results in premature wear.

General Motors has conducted extensive injector cleaning studies to determine effectiveness. There is no confirmed evidence that cleaning Multec injectors has resolved a vehicle driveability problem. In addition, suppliers of various injector cleaners may claim that their product can also clean intake valve deposits. General Motors laboratory tests have shown that injector cleaners have little or no effect on intake valve deposits.

General Motors maintains the position that Multec injectors should not be cleaned.
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Being fairly mechanically illiterate, I don't know if these are the injectors used in the 2.8 or not. But it was listed under the 1988 Fiero heading.

There are all kinds of bulletins listed on this site. I found one for the 1988 steering rack bushing, the TCC locking problem, plus too many others to begin to list. The service manual was not availible however Very interesting stuff!

I have heard this about multec injectors also, that some cleaners can dissolve the insulation on the windings. If you take the injectors out, and send them in for cleaning, they will do a much better job, and not dissolve the insulation. This is mostly for injector cleaner gas additives and systems that run thru the fuel system.

Whats the web site address???

Interesting. I use a pour in cleaner about 2 times a year. Maybe Ill quit doing that for now. Did they say any maybe low alcohol one that could be used?

If I am thinking right the fiero 2.8's came with the pintle type design injectors as original equipment. You can use multec injectors as replacements (as I did - I got multecs out of an '89 3300). I have seen stuff on the web about both types being cleaned - I am not sure if the pintle type have the same problem with the insulation dissolving.

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Murphys Law - "Nothing is as easy as it looks, Everything takes longer than you expect, And if anything can go wrong - it will, At the worst possible moment!"

quote Originally posted by FrugalFiero: If I am thinking right the fiero 2.8's came with the pintle type design injectors as original equipment. You can use multec injectors as replacements (as I did - I got multecs out of an '89 3300)...

Bingo!
V-6 Fieros came with pintle type injectors. I've heard rumors that some of the 88s came with multecs, but have never seen any evidence of it.

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Raydar
88 3.4 coupe.

Coming soon...
88 Formula, presently under the knife.

www.motoralldata.com i would bet. not positive if this is the one he is using but my friend went to school for auto mechanics and they used this site ALL the time, it's got TSB's, recalls, wiring diagrams, about EVERYTHING you need to know about any car almost. you have to pay for it but we kinda got a deal on it...really good site, if you do alot of work on cars, it's well worth it. it's almost like having a service manual for every car at your fingertips.

quote Originally posted by Raydar: Bingo! V-6 Fieros came with pintle type injectors. I've heard rumors that some of the 88s came with multecs, but have never seen any evidence of it.

This site leads me to believe that "Multec" are in-fact "pintle-type" injectors.

http://www.caspeed.com/multec-injectors.html

Most 88 and some 87's had the Multec Disk injectors.

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85GT 2.9 4spd MSD Everything, Big Cam and Nitrous. www.captfiero.com

quote Originally posted by Mark: This site leads me to believe that "Multec" are in-fact "pintle-type" injectors. http://www.caspeed.com/multec-injectors.html

That's interesting. I have always understood (perhaps incorrectly) that multec were disc type.

quote Originally posted by Capt Fiero: Most 88 and some 87's had the Multec Disk injectors.

How many '87 or '88's have you actually seen with factory disk style injectors?

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Jeremy B.

quote Our experiences and our opinions differ. No problem; we can agree to disagree. However, please don't take the position that anyone who disagrees with you is an idiot. ---MrPBody

quote Originally posted by FrugalFiero: If I am thinking right the fiero 2.8's came with the pintle type design injectors as original equipment. You can use multec injectors as replacements (as I did - I got multecs out of an '89 3300). I have seen stuff on the web about both types being cleaned - I am not sure if the pintle type have the same problem with the insulation dissolving.

exactly - hope this didnt scare anyone - this is only for people who have replaced their injectors. All injectors can lose the insulation on the windings, but the GM Multecs are notoriuos for it. And, not saying it WILL happen, but, depending on the strength & concentration of the cleaner used, it MAY happen.

quote Originally posted by Fierotech: How many '87 or '88's have you actually seen with factory disk style injectors?

To be honest, all 88;s I have evern seen apart had the disc injectors, and I have seen a couple of 87's with the disk injectos. I spoke to the owners on a few of these cars and they claim they have never changed the injectors. Now anything is possible but the things I have scene with my own eyes lead me to this conclusion.

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85GT 2.9 4spd MSD Everything, Big Cam and Nitrous. www.captfiero.com

quote Originally posted by Kerry: Whats the web site address???

Actually it's a "GM" site that only employees can access.

quote Originally posted by Capt Fiero: To be honest, all 88;s I have evern seen apart had the disc injectors, and I have seen a couple of 87's with the disk injectors...

Interesting. My Formula parts car had pintle type injectors. I've got another Formula that I'm working on, but haven't pulled the injectors, yet.

Hmmm... I'm still working on a theory.
Do you remember what sort of connector the injector harness had, on the engines you saw? I'm referring to the connector on the injector harness that connects to the main engine harness.
It could either be square or flat.

quote To be honest, all 88;s I have evern seen apart had the disc injectors, and I have seen a couple of 87's with the disk injectos. I spoke to the owners on a few of these cars and they claim they have never changed the injectors. Now anything is possible but the things I have scene with my own eyes lead me to this conclusion.

As an 88 owner who raplaced the stock injectors, I can assure you that atleast my 88 (according to the VIN it was in the last 200 made) had pintle type injectors. And I had a 3 system cleaner used (intake/gas/oil) on that engine and they held up perfectly fine. I switched to the Mustang #19 disc injectors when I swaped to the 3.4l.

-Rick

I have owned many '88 Fieros (probably close to a dozen Formulas & GT's) and have never seen a disc-type injector in any of them (and I tore apart almost all of them). For a while it was a popular swap and purportedly increased power by switching to the Multec (disc type).......there is much debate as to whether or not this really did increase power though.

Anyway, I am 99.9% sure that ALL V-6 Fieros came with the pintle type of injector, not the disc or Multec version.

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Interesting debate on the bosch pintle vs multec injectors in the 2.8L motors.

At one point, I thought the 87 and 88 2.8L motors had multec injectors. I do remember reading a service bulletin a few years ago about the use of multec injectors from the 87 model year on in GM port injected motor applications.

The description on identifing the injectors ( I forget word for word ), but is that the old pintle style have a stepped injector body where the multec injectors are a uniform cylinder shape with a blue band around them.

I know every 2.8L Fiero motor I remember seeing had the stepped body injectors, and all of the late model TPI motors I seen used the uniformed round bodies with blue bands on them.

Just reading in the 88 Helms manual now, it does describe how the injectors operate, and although it does not state it is the pintle, or multec injectors, the description is for a pintle style injector.

Interesting enough, the P22 does show both the Bosch pintle style, and the Multec style in the illustration part of the parts diagrams, but it does only list the one injector number for 85-88 2.8 vin 9 in the parts breakdown in the front of the book.

It is well known that some solvents, including comercial product marketed for this use, can ruin GM injectors. How Well Known?

Delphi (GM's former parts divisions spun off) has made a special point of mentioning that the current generation of Multec injectors has been redesigned to prevent this specific problem. ( www.delphiautomotive.com )

This was also covered in either MOTOR or MotorAge (Before the latter went byebye). In short... Everything they could find said that most cleaning methods are useless. If the additives required by law in U.S. fuels won't cut it then nothing else likely will either. At least no that you can put in an engine.

allot of it has to do with how fuel evaporates and heat soaking.

Fuel isn't a single compound and the components evaporate at different rates. The heavy stuff is slow and most likely to get cooked on/into the injector. If it gets bad, cleaning it is like trying to disolve concrete.

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Edison Carter: When did the News become Entertainment?
Murray: Since it was invented.

The Ogre's Fiero Cave (It's also at the top of every forum page...)

quote Originally posted by Capt Fiero: To be honest, all 88;s I have evern seen apart had the disc injectors, and I have seen a couple of 87's with the disk injectos. I spoke to the owners on a few of these cars and they claim they have never changed the injectors. Now anything is possible but the things I have scene with my own eyes lead me to this conclusion.

Pretty interesting. Must be just the Canadian Fieros that had them. (not saying that's not possible...a VERY small fraction of what I see is Canadian cars) I believe it is probably safe to say that I have worked on an un-countable number of Fieros in the last six years (Mike, you were there for a while, would you venture a guess how many I've worked on or dis-assembled?!?!), and the only ones that have had disk style injectors were Tomcos or verified installed by the owner. The ONLY car I have come across that had disk style injectors, and was proported to be that way from day one, is an '86 GT 5speed. The owner insists they were never replaced. We installed a 3.4L in his car, and he also insisted the disk injectors be retained in the swap (against my recommendations) since he felt that may be the reason he felt his car ran so well.

After bringing the car back a few times for idle problems, each time not wanting to hear my answer (that the injectors were causing it), he finally gave up and had me put stock 2.8 injectors back in...and lived happily ever after.

And, Raydar---good theory, but no. The square (late style) plugged cars I've seen have pintle injectors, too.

Take care all---
Jeremy B.

quote Originally posted by Fierotech: ...And, Raydar---good theory, but no. The square (late style) plugged cars I've seen have pintle injectors, too.

Cool! You saved me some trouble. I was going to pull my plenum and fuel rail while I was doing some other stuff, and check.

Nevermind

quote Originally posted by Fierotech: Pretty interesting. Must be just the Canadian Fieros that had them. .

Must be the West Coast Fiero's that had them, I'm pretty sure I've never seen an East coast Fiero motor with Multec injectors

This is the website, but you have to work for GM to gain access to it. I do have access if anyone needs info from it. It is chock full of information.
http://service.gm.com/index_en-US.html

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Blue 87GT - currently restoring
Red 86SE - currently parting out

I also believe that right around 87 was the time GM came out with multecs, so knowing GM, we could have seen multecs factory installed in any GM MPFI vehicle at any time...ya know...whatever was on the shelf. My 88 Formula had 2 multecs and 4 pintle type in it when i pulled it apart. Like I said...whatever was in the parts bin.

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Murphys Law - "Nothing is as easy as it looks, Everything takes longer than you expect, And if anything can go wrong - it will, At the worst possible moment!"

My Formula with the square injector harness plug had pintle style injectors. I've never seen a Fiero engine with the Multecs, but Jeremy and Mike would be the two guys I would put all of my trust into in this debate. I'm planning to make a visit down there in another month or so Jeremy. Maybe we'll run into each other. I recently remembered I was never billed for some emergency brake work I had performed a year ago while on a vacation trip to FL.

Here comes "a picture says a thousand words" man!

You can now clearly see the difference between the two. Even with your engine 100% assembled & in place, just look between two of the upper plenum runners, and you can see the injectors. With this picture I just took, you can now clearly tell which type you have.

I personally have the disc type, and love 'em. Never had any troubles at all with them.

[This message has been edited by watts (edited 02-13-2004).]

quote Originally posted by Rainman: I recently remembered I was never billed for some emergency brake work I had performed a year ago while on a vacation trip to FL.

Hey Rainman......I actually still owe you as well! PM me your address so we can square up. Or LMK what you owe Jeremy and I'll cover it.

I'll send you a PM, Mike.

I don't think Jeremy was there when I made my unschduled "visit."It was early on a Saturday morning, and Ed said he would send me a bill in the mail, which I realized the other month I never received. So I figured I would write a check for what I felt appropriate for his good-will of billing me when I got back from vacation. But decided its been too long since I've been there, so I'll drop it off in person.

[This message has been edited by Rainman (edited 02-13-2004).]

quote Originally posted by watts: I personally have the disc type, and love 'em. Never had any troubles at all with them.

One for the Canadian Theory!

(can you verfiy weather they were "stock" or not?)

Jeremy B.

Oh, and Tim, 2 discs + 4 pintles = someone worked on the car.