Just an update...went back to stock cam timming and found a big difference! Torque back but no Dyno yet. Called the Dyno shopjust see what the speed was on the dyno...6300 @ 141MPH in 4th gear. If he ran all the way to 7500rpms it would be higher. I'll get the mixture set and run it again.
Steve...What gear were you running on they dyno? Tech said it would influince the Torque rate if in another gear. I don't know for sure but thought I'd ask.
I was going to switch the valve covers like yours but found out i cant because of the cam sensor on mine is in the way. Just FYI.
quote
Originally posted by Steven Snyder:
Nice!!! BTW loss through the tranny is 15-25 hp.. so you're around 240 or 245 crank. What happened to all your torque? Are you running the 13* exhaust cam retard? We have pretty much the same intake (my only major mod).. but I have 30 more ft-lbs and 3 hp more peak torque... hmm.
Originally posted by Steven Snyder: You should try running an oil that is slightly thicker than hot. You likely have a bad lifter with a bad check valve since when your motor heats up it always ticks, but slightly thicker oil could be enough to prevent it from tapping unless you really beat on the engine.
Thanks for the advice, I put 10W-30 in today. It made all the difference in the world.
Typically, when I start the engine, for the first second, it sounds terrible, alot of racket back there. And, like I said, after 20 minutes, it has a nearly permanant tick till the engine is cooled all the way off. If I abuse it even a little the ticking gets out of hand, so I always take it easy once it starts ticking.
Now... It barely makes any racket on startup, and I have yet to hear it tick, and I gave it a pretty good flogging too. I don't know if its just that the temperature today was about 30 degrees cooler then last week, but all signs point to the 10W-30 being the answer.
Oddly enough, and this is important... I found that the oil cap that came with this motor (from a 94 lumina 3.4 Euro) advertised 10W-30. Meanwhile, me in my infinate wizdom, used nice clean oil cap off my crate 96 DOHC, which advertised 5W-30. And I used the 5W-30 that the wrong cap reccomended.
This also kind of explains the usage of the oil cooler on the earlier DOHC's.
Trying for a first startup. Key in the ON position I have a momentary fuel pump and the SES light is on. On cranking the tach does show RPMs. No apparent fuel in the cylinders. I checked for B+ 12V at the injector plugs and I get a light. I tried the test light across the injector plug while cranking and no blinking or steady light. The next test is continuity of the injector driver circuit from the ECM to the injectors.
If I have continuity the manual says I have a bad ECM. Can that be true? How often do ECMs take a dive?
~Neil
------------------ 1988 GT, 5-speed, white, beechwood leather, 3.4 DOHC 6-speed installation in process. Really. I am working on it.
I had the exact same problem with mine. You may have 12 volts on the injectors, but the computer grounds them, which fires the injectors. You need to see if your 12 volts are making it to ground. Find the injector ground pins on the ecm pinout, I think they are on the D connector. make sure these are grounded, and are getting 12 volts intermitttently when cranking the motor. If they are, your ECM is okay. If not getting grounded, you also need to double check you wires coming from the ignition module to the computer, and your crank sensor wires running to the ignition module. If these are all okay and you still aren't getting any injectors to fire, I would suspect the ECM. On my car, I had two wires backwards coming from the ignition module, causing the exact same symptoms. Double check everything you can before shelling out the money for a new ECM.
Thanks, I hadn't thought about the ECM being properly grounded. I read "replace ECM" in the manual and it seemed to come to that point really fast. I forgot that was based on everything else being factory correct.
Quick question and I think I know that answer but I just want to make sure before I buy the parts.
I have a '96 DOHC and I am now getting ready to put it in to the project car but I have to get the accessories for it first. I have a harness coming from Erik so that makes the electrical a lot easier.
Questions:
1. I put the 3.4 DOHC alternator in and not the stock Fiero. The wiring harness, I am 90% sure will match up to the 3.4 alternator not the Fiero. Will there be any other problems with the charging circuits to ECM etc. if that one is used? Anything else I need to do I guess is what I am asking. Don't think so, but better safe than sorry. 2. I have a Fiero V6 A/C unit in the car so will this one fit into the A/C mounting area on the 3.4 without major rework?
Again, I think these are route simple questions and I am sure they have been answered already in this thread but I could not find the page that had the answers.
Don I used the Z34 alt. and the stock Fiero A/C compressor. But mine was a Duke Compressor the belt fit fine and I wired the system to use the stock sensors, if you are not doing the wiring then that might be a problem.
I have Erik from the forum here building me one of his standard harnesses and I gave him everything I have like A/C etc. but I did not ask him about the Alternator. I'll go grab a Z34 Alt tomorrow and get ready to put everything together over the next few weeks. I bought the idler pulley and serpentine belt the other day so I am getting ready to put this into the project.
Just a question. If the compression ratio was incressed to say.................10.5-1 . What would the expected hp increase be? Stock is around 9.5 right? Would pump gas be a option?
Just a question. If the compression ratio was incressed to say.................10.5-1 . What would the expected hp increase be? Stock is around 9.5 right? Would pump gas be a option?
I was about to say.... "I know he's not revving that engine cold....." Then you said it was warm. Really a nice ride Bob, you did a wonderful job building it. I hope it goes to a good home, and the proceeds to a good cause.
I was about to say.... "I know he's not revving that engine cold....." Then you said it was warm. Really a nice ride Bob, you did a wonderful job building it. I hope it goes to a good home, and the proceeds to a good cause.
Well I had to get ride of it for legal fees. I really didn't want to sell it. But my daughter is more important and there is no comparison. I will miss it but hey I'll build another one, one day. The guy who bought it is really going to be thrilled when he sees it. He's only seen it on the internet so he is yet to see it in person. If i were him, I'd jump up and down like i won the lotto.
SOLD.
[This message has been edited by procarnut (edited 01-07-2009).]
hello fellas- let me begin by saying I'm what you guys would call an "old timer" at age 47, and I grew up on SBC's and 400-455 Pontiac V-8's and Olds 350's, with carburetors- and started driving back in 1978. 5 years ago I bought a 1995 Pontiac Grand Prix (being a Pontiac man, IMHO a Pontiac is better than any Chevy product). To date the car has never failed to put a smile on my face while driving it. I am simply AMAZED at the power and torque this V-6 3.4 DOHC engine has for its size. Now keep in mind I have a Firebird w/470 CID engine that makes 500 HP, w/tunnel ram- so I'm not easily impressed. I drive the GTP with the EGR valve unplugged and it has more part throttle torque for sure- it throws a code and CEL, but who cares. Bought it at 102,000 and drove it HARD to 178,000 miles, when the trans gave up the ghost- and still drove home with the only remaining gear, low. The car gets 18-20 MPG beating the snot out of it, and 27 mpg with my wife/kid in the car highway cruise speeds. Stuff started breaking on it, i.e. console lid hinge, glovebox latch, hood release cable, emergency brake cable, CD player- but mechanically it just keeps running. We found a trans w/45,000 miles on it an swapped it in, it's running again- I drove it again yesterday. Still original paint and looks ok too- but being a family man, decided to get a newer car- and bought a 2001 Monte SS 3800 S2 NA car.
well the old Pontiac will SMOKE the newer 3800 Monte, even though both weigh the same. 210 HP vs. 200 HP, but the Pontiac 3.4 DOHC always felt more like 235-240 HP to me. My first car back in 1978 was a 1970 Chevelle w/307 CID 200 HP V-8, and this 3.4 DOHC definitely would run with or better than my old 307 as well.
With a heavy heart I listed the 1995 GTP in the local paper for $1800 and immediately got at least a dozen calls. Last night somene came up and test drove it and was impressed, I nailed it, it wound out, and he asked "does this have a supercharger on it ?" I said "no, it has four cams". Mechanically I always kept up on it, i.e. new parts- timing belt, starter, water pump, a/c compressor, alternator, CAT, struts, wheel bearings, tie rods, sway bar bushings, radiator is all replaced- and now a trans. Also rotors/brakes every 2 years or so and tires, it's been a really great car.
With GM nearly belly up, and talk of dropping the Pontiac and Saturn lines, cars like GTP and Fieros would become instant collectibles if that happened. Like the old saying goes, if "they stopped making it"- it becomes a thing of value. We used to pass on old 'Cudas and GTO's back in the 1970's for $300, look what they go for now. Who knows ?
You guys impress me with your knowledge of these engines and how you swap them into Fieros. I've rebuilt a ton of old V-8's but never toyed with the computer aspect of today's cars. Keep up the good work, I read your posts and actually learn.
On the aspect of DOHC vs. SC- it's always better to make equal power if you can, with an NA engine- less complexity, less parts to break- and not as prone to spark knock- today's fuel is crap, and not supercharger/turbo friendly overall.
The 3.4 DOHC is a very under-rated engine. It was built along the lines of the old 1960's musclecar engines, i.e. look up FORD SOHC 427. Hemi type heads, OHC's, made 680 HP in crate motor form. The DOHC is a modern version of it, albeit with today's fuel mileage/emissions concerns taken into account and design.
The new SC 3800 makes more HP, yes, but there's something about 4 cams and running it "on the motor" only that's better. Anything makes more power with a blower, even a lawnmower engine. Making respectable power NA makes a more valid statement IMHO.
well I'll go back to lurking for now. Let me just say I feel priviledged to have "stumbled" across this GTP 5 years ago for $3400, and it's been a great car, still runs great, and the 3.4 DOHC is an engine I'll never forget. If I had the time, space, and money to burn, I'd keep it. Such is the realities of family life. I put it up for $1800 and decided firmly not to budge on the price. The kid who looked at it yesterday, wants it and is trying to gather up the money. Looking back it's been a good investment.
take care, thanks
ps- I got a funny thought last night- a DOHC with custom sheetmetal intake, and one Holley 4-barrel on it, imagine that, how would it run ? (chuckle..)
[This message has been edited by no-EGR (edited 02-27-2009).]
Hey Paul (EMC209i) why did you delete your original posts in this thread. Now I have to use the search to find the threads I wanted to reference, and that plain stinks. Whats the deal? This engine leave you that sour?
------------------ 1986GT 4-speed DOHC and 1987GT Auto
[This message has been edited by FieroWannaBe (edited 03-29-2009).]
I let a few issues cross my mind but now that springs on its way I want to address some of my swaps issues. Upon a cold start in the summer time my engine would run perfect and it wouldn't stall or miss a beat. But over the 2 months I drove it with the swap I found that after the engine had reached operating temp it would start missing and popping and if I shut it off it would crank and crank but wouldn't fire. Now this to me sounds like a COIL PACK issue. I think that the coil packs are getting heat soaked and start making the motor miss and eventually stop working till they cool off. After letting the car sit for like 20 minutes it'll fire up again no problem, my coil packs are in the stock location, has anyone else had this problem and what did you do?
Quick question, Just did a datalog while running the $DF 16149396 BCFA. At idle, my timing is erratic. It ranges from 15 to 27 degrees. The MAP is stable, RPM is stable and O2 is alive and responsive. I just can't find a good reason for it to be commanding such random Spark Advance. It'll swing across that degree range many times a second. The same condition on the $2E BKLL code yields a perfectly stable 27 degrees. Something seems wrong about that. Does anyone else have a good BCFA datalog I can look at?
I took over procarnut's DOHC fiero about two weeks ago. He did a bang up job on the swap and it is a thing of beauty.. I've got some modifications to do to the interior (i.e. remove the subwoofer so my 6'3" frame can fit), get some wider meats on the rear, put a spintech on it (bit too loud of an exhaust for my taste), and get some koni's and springs on it.
Those Flowmaster 80's with a 3" pipe are louder than my old 87GT with true 2" duals with glasspacks and no CAT.
Driving Impressions: First off the car's tune is a bit off due to larger injectors being installed with no retune of the ECU, furthermore Procarnut turned the cams back to stock so most of the low end torque is back. I drove 4 V6 Fiero's from 1991 - 2002 and even purchased a 96 DOHC engine to put in my 87GT but wussed out, sold the engine to QwkGTA and the car to a teenager and went the MR2 Turbo route. Yes the Toyota was more refined and the turbo was quite a rush when all the BPU's were installed but driving a 4cylinder that requires a turbo to even wake up in and about traffic was not fun.
On to the DOHC. For those of you who are on the fence or would like a driving opinion from someone who has only driven the 2.8 V6 in fiero's, MR2 turbo with about 240hp to the wheels, and a stock 93 RX7 TT and even a stock NSX many times... from my modicum of amateur SCCA and PANOZ racing school background this is the engine that should have come with the fiero from the factory. This engine is SMMOOOOOOOOOOOTH..... The closest analogy I can think of is when you cut yourself with a razor, you don't realize you've done it until you look down. The DOHC power rolls on so evenly you don't even realize what you are doing until you look down. The engine feels like a hot 3.4PR until about 3500 and then.......... nothing spectacular happens....it just keeps reving and pulling stronger and stronger. Is a 3800SC faster off the line?....all day long....will a N* leave it in the dust....you bet....but this engine, in the fiero frame, is all about balance and it also serves as a great canvas to start modifying. i.e. Matt Hawkins.. I've only taken it to about 6500rpm where procarnuts dyno graph AFR starts to really thin. There is no surge or rush of a tweaked turbo MR2 or RX7 just even, smooth, easily drivable torque, much like a stock <97 NSX with an extra .4 liter's down low, a pair, and no VTECH, especially the way procarnut mod'd the intake and exhaust. Not to knock any of those imports as each one of those deserve a tip of the hat in respect, especially when taken to the next level of modifications. It's the classic case of "its exactly what I wanted but not what I expected." I was preparing myself for a real peaky, wind it out motor, similar to a celica GTS or S2000... not the case. It doesn't have the copious amounts of torque at all rpms like a N* but that swap is another level of difficulty too.
Ok enough blubbering over an engine that's "only" putting about 220 to the wheels. (I've been driving 4dr family sedans for 3 years now)
The ECU is from a 97' engine which when I've cross referenced the part # its the same ECU on the 97+ 3800 ECU's....wouldn't that mean that the ECU could map positive manifold pressure given forced induction? I may be waaay behind the curve on this as usually when I think I've had an original thought, its been done long before my meager gray matter came up with the idea.
Oh yeah....the C5 brake upgrade that procarnut festooned to the suspension is quite nice....I've never stopped comfortably in a fiero, even with the PISA upgrade, but the C5 brakes on a fiero bring it to a stop much like the PANOZ GTRA's I've driven at road atlanta. I haven't gone from 140mph to 30mph like I have in the GTRA's where your vision blurrs initially due to deformation in your eye balls because of the decelleration G's, but these feel damn close.
For anyone who is sitting on the fence on this swap...do it.....do it right...but do it....and don't puss out on it like I did 8 years ago.
Wow! Thanks for posting. After reading that maybe I'll have the push to finish mine up. I keep getting bogged down with modifications to the stock parts. Currently I'm modifying '96-'97 cam covers to use on my '92 motor. Of course, doing this means I have to move this . . . and then I'll have to modify that . . . which means I have to re-powder coat the part . . . and on and on.
I picture myself on a psychiatrist's couch with him saying, "I don't know; why do you think you can't finish your car?".
Great review, msweldon! I'm a die hard V8 fan, but then that's what I have my Trans Am for. Now that I've got another car for my V8 fix, I'm seriously rethinking a 3.4 DOHC swap. What I'd really love to see is someone using a new 3.6 DOHC 300 HP engine in a Fiero.
Now that I've got another car for my V8 fix, I'm seriously rethinking a 3.4 DOHC swap. What I'd really love to see is someone using a new 3.6 DOHC 300 HP engine in a Fiero.
I agree on both points. I've decided to do a slow build up of a LQ1 for my t-top...
but I'm convinced that once Camaros start getting wrecked, those LLTs should find their way into a few Fieros.
------------------ 88 TTop coupe (96 3.4DOHC/5 speed "almost done)" 03 Vibe GT. 6spd (stock) 05 GTO, LS2, 6spd (not stock) 84 SE "Vert" (oh boy, what did I do now)
Ok, had some time to start going over the swap bit by bit to see what procarnut did. While cleaning up the engine bay (ouch that Texas dust gets everywhere) I noticed where the passenger side deck hinge is cut back to make room for the timing cover, the timing cover looks to have a few cracks in it where it looks like the timing cover smacked the hinge under load. procarnut cut the hinge to a very tight tolerance so it doesn't suprise me that this happened. I've seen other swaps with the same problem.
My question is, where can I order a new timing cover, to more exact, just the front upper half of the cover? I've tried gmpartsdirect and gmpartsonline with no success. There are no pick n pulls nearby for me to scavange so I figured I'd just go ahead and order one.
Also, besides junkyards, have any of you found any respectible and low cost sources to order parts from online? My local GM dealer parts department has a major chip on their shoulder as if ordering "anything" is a pain for them to execute.
Lastly, is there a repair manual for the LQ1/DOCH online anywhere? If not, has anyone found a good source for DOHC shop repair manuals?
Just getting started on a 91 3.4 DOHC into a 87 Coupe with a Isuzu 5 speed. What's the part number for the Dodge Truck mounts? Do the poly mounts sit too high?
4.9, Not sure what folks have against the Poly mounts. I have them and they seem to work fine for me. I bought a set of WCF 2.8L poly mounts, and used them on my 96 DOHC motor. Fit just fine. No issues. No cutting, no fab at all. Just use some good "Grade 8" type nuts/bolts as needed and you should be fine. I also bought a set of Rodney Dickman mounts because I wondered if they would fit better, but they are the same overall size, they just do it differantly. I wish I had bought the Rodney ones first, because I like his style better, but again, I don't think the WCF ones are bad.
Please?
