I bought an engine from a forum member here last year. It's a modified 3.4 pr. To make a long story short, because he doesn't want to send me parts he owes me, he wont respond to my emails, so I can't get answers to my questions. The engine has had issues since I installed it. It acts up on start up, wanting to die and lacking power, then clears up when the engines been running for a bit. I also get an intermittent code 32, particularly after long highway drives (45+ min). I can continue to chase issues, but I think there's an underlying issue of tuning. The engine was supposed to come with a tuned Fiero ECM and a tuned 7730. The PO claims they both fell out during shipping. In any event he sent me a 'spare' ECM which also happened to be tuned, so he claims. He claimed before he stopped responding to my emails that the engine was tuned to run on 'high octane' though he also said it would run on any octane. I'm not an expert on this, but my understanding was that you shouldn't run an octane other than what its tuned for. My problem is I don't know if I'm even running the correct octane because I don't know (1) if the ECM I have is even tuned, and (2) if it is tuned, what octane its tuned for. The for sale thread was edited to remove details of the mods, so I really don't know what was done to the motor. What I have verified is that the engine is a 3.4, has a Truleo intake and has roller rockers. What I do remember him claiming it had was a Crane 272 cam, double roller timing chain, a stronger bottom end, pistons and 'bigger' injectors. Don't know if that means stock 3.4 injectors or more. I do seriously doubt the HP claims the PO made. Its a quick car, but likely not the 208 whp he claimed (more likely 208 crank).

So, my question are as follows:

Can I tell whether my ECM is tuned or not?
Does it matter what octane I run? (I've run everything from 87-93 and noticed no change in performance, mileage or other issues).
I've been contemplating a 7730 swap, and I'm wondering if I should just go ahead with that, or if the underlying issues will find there way through, complicating dialing in the 7730.
What mods are relevant to a tune?

I would appreciate any help on this. I don't want to start a flame war with the PO, argue hp claims, etc. Despite some issues, overall I'm happy with the motor I got. What's done is done, I just want to get my car running right.

A quick check can be to look at the PROM in the ECM and see if it still has the GM sticker on it. If so the prom is quite likely stock.

Another thing to check is the mechanical abilities of the engine...a compression test.

There are a lot of things that could cause this. Just to name a few off the top of my head...
ECU tunning
compression
ignition timing
camshaft timing
fuel mixture (leaky injector or fuel pressure regulator, faulty O2 sensor)
restricted intake or exhaust
bad grounds
ect, ect, ect.

The process of elimination will be your friend.

The octane needs of your engine is based solely on the compression ratio.

If it's over 10:1 - run 93 or higher, if you get good performance on lower octane ratings, use them. The stock 2.8 and 3.4 used 87 octane.

Does the car have the cold start injecter circuit still in place?

If you're using a Fiero ECM, you need to have the cold-start injector installed. Otherwise, the engine will have a hard time starting when cold.

The Code 32 on the highway is probably related to the EGR. If the EGR is not installed, or is not working, that would be the culprit.

The stock 3.4 V6 was designed to run on 87 octane. The only reason you'd need higher octane fuel would be if the compression ratio was increased. ECM tuning, in and of itself, will not dictate a certain octane level. But rather, the ECM would be tuned to run on whatever octane is dictated by the compression ratio.

Sounds to me like the person who built the engine may not know as much as he thinks he does. And he probably shoveled a lot of BS in your general direction.

[This message has been edited by Blacktree (edited 07-11-2011).]

Code 32 actually means a problem with the EGR vacuum control solenoid, not the EGR valve

https://www.fiero.nl/forum/Forum2/HTML/045528.html

If you're getting a code 32, you probably still have the original Fiero ECM installed, and the chip is probably stock. Taking out the center console would tell you. Does the car still have the Fiero EGR valve, or the digital one? Does the engine still have a distributor, or DIS?

Ryan at Sinister Performance can burn a custom chip for the 7730 ECM, but you'll want to figure out what cam you have first. My guess is stock.

http://www.gmtuners.com/

Thanks for all of the quick responses. A lot of things to check into. I should have mentioned the car bucks cruising at low rpm's, then clears up as you get on the power. It does it some times, not just on cold starts and it seems to come and go without any particular pattern. I do still have the cold start injector installed. No problem with cold starts. PO claimed EGR wasn't disabled on the tune, and I do still have the vacuum system connected. It does have a braided EGR tube and stainless lines.

Check your plug gaps. If he was running .060" for DIS, you should be at .045" using a distributor. Make sure all your plug wires are in good condition too.

Plug wires are new. Plugs are new as well. I gapped them.

You run the lowest octane rating where you don't get "pinging" IE: run 87 if it 'pings' go to 89, if it pings on 89 etc... if it pings on the highest octane you have other problems. There is NO POINT to run a higher octane than needed. the only time higher will help is a high CR, boost, nos, you increase base timming, or if your ECM is pulling timing due to knock. Fieros don't run a knock sensor so it doesn't help. The higher octane the less flamble the gas so to speak.

Code 32 is the EGR solenoid, (under the coolent fill cap) the EGR itself does not throw any codes. Coolent drips on the solenoid and corrodes it)

you need to figure out what size injectors you have, even it it means pulling one out and looking at the part number on the side of it.

You really should get an ALDL cable and WinALDL. Scanning it would be the only way to get a very basic idea of the tune, unless you can find someone with a prom reader, that would be ideal. then you can tell everything that was or was not changed.
Even if you swap to the 7730 you will need to learn how to log the ECM. may as well start now.

At this point the only thing really relevent to the tune is fuel injector size. after that, mods really have to be logged and dialed in.

------------------
"DRIVE IT LIKE A FIERO"
'84 Fiero, engine to be determined
'87Blue GT 3.4L Swap Completed!!!!!!!! Boosted!!!!!!!
^^^^ Now in the Construction Zone^^^^
Las Vegas Fiero Club Parts/Sales/Service/Club
Fiero Road Club Of Northern Nevada

quote Originally posted by onesexyfiero: I bought an engine from a forum member here last year....he wont respond to my emails, so I can't get answers to my questions....What I do remember him claiming it had was a Crane 272 cam....I would appreciate any help on this. I don't want to start a flame war with the PO, argue hp claims, etc. Despite some issues, overall I'm happy with the motor I got. What's done is done, I just want to get my car running right.

quote Originally posted by RWDPLZ: Ryan at Sinister Performance can burn a custom chip for the 7730 ECM, but you'll want to figure out what cam you have first.

quote Originally posted by onesexyfiero: How can I tell what I have?

Here is one way:

There should be some identifying numbers and letters scribed in at one or both ends of the camshaft. Please record carefully those you find at the ends of the camshaft and post them here. Then I or someone else probably will be able to determine what cam it is that you actually have in your 3.4L engine (or at least whether or not it's the Crane 272 cam that the previous owner claimed was in it), OK?

With keeping a distributor, you can run a 7730 using a properly programmed $88 prom.

I do have a cable, but I don't have the software yet. I never noticed any issues with any octane, just the same intermittent issues described above. It might be a little bit before I have a change to get the Fiero into a garage and check for all the stuff you guys have suggested. Stayed tuned, and I appreciate everyone's continued support.

Here is the software download for WinALDL

http://winaldl.joby.se/

Click the download button.

You do need something different to scan the 7730 however.

ECM has a chip which sits higher than stock and prevents the stock cover from fitting, so it has foam and longer screws on it. Says "Atmel" on the chip.



5 Injectors match. One is different for some reason. 5 Don't have any visible numbers on them (I didn't pull the rail). The one different one has the number "01D073B" on the side. Not sure if they're O's or zero's.



Pulled the three easy plugs (back bank) and they're all white. They don't look as white in the picture, but it looks to me like its running rich.

I have a cable and I downloaded and installed the software. I'll try and figure that out and report back this week.

Well that definitely is not a stock chip.

quote Originally posted by onesexyfiero: http://www.amazon.com/Fuel-...Camaro/dp/B001DW22SM Injectors (well 5 of them anyways) look like these OEM Firebird ones that would have come on a 3.4. These are a couple of pounds higher than stock Fiero, correct?

Correct, the 3.4 uses 17#, the Fiero uses 15# stock