I have the 3.4 DOHC in an '88 that isn't running quite right. I want to test the sensors. I know where these sensors are: MAP, TPS. Where are the rest? Anyone have a schematic/picture?
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11:33 AM
PFF
System Bot
phonedawgz Member
Posts: 17091 From: Green Bay, WI USA Registered: Dec 2009
IAT - in the intake path MAF - If you have one - in the intake path IAC - not a sensor but in the throttle body CTS - Intake manifold under the throttle body. It either has a two wire Yellow/Black or three wire Yellow/Black/Green wire connector on it. O2 sensor - exhaust manifold CMP - Cam Pick Up Top of the front head - if you have one (94 - 97) CKP - behind the balancer - but it has a tail to a 3 wire plug - if you have one (94 - 97) Crank Pick Up - Two wire pick up for the ICM - Middle front side of the block - Has a two wire connector on it, Yellow and Purple, usually twisted, that runs to the ICM. The sensor itself is in the block with just the connector showing outside the block. All years have this. Oil Pressure sensor - Front side of the block - three wire sensor usually for a Fiero swap. This sensor threads in and is totally outside the block. Evap Purge Solenoid - Might be right next to the throttle body inserted the intake manifold (96-97), might be bolted to the intake depending on the year. If external it might be located anywhere on a swap including the firewall or transmission. If inserted to the throttle body it has a single vacuum line connected to it. If not inserted, it has two vacuum lines to it. If you have a red connector, that is the Evap purge connector. The wires to it should be Green/White and Pink
[This message has been edited by phonedawgz (edited 08-19-2012).]
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01:46 PM
n7vrz Member
Posts: 521 From: Dixon Springs, TN Registered: Dec 2010
Originally posted by phonedawgz:MAF - If you have one - in the intake path
Engine is '93 so MAP not MAF. Should've included year. My bad.
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Originally posted by phonedawgz:IAC - not a sensor but in the throttle body
I know where it is but didn't include since it isn't a sensor. But tnx anyway.
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Originally posted by phonedawgz:CTS - Intake manifold under the throttle body. It either has a two wire Yellow/Black or three wire Yellow/Black/Green wire connector on it.
Haven't found it. There is a sensor in the coolant stream but is in the intake manifold. CTS or another sensor?
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Originally posted by phonedawgz:O2 sensor - exhaust manifold
Yup, another I forgot to say I knew where it is.
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Originally posted by phonedawgz:CMP - Cam Pick Up Top of the front head - if you have one (94 - 97)
'93 engine
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Originally posted by phonedawgz:CKP - behind the balancer - but it has a tail to a 3 wire plug - if you have one (94 - 97)
'93 engine
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Originally posted by phonedawgz:Crank Pick Up - Two wire pick up for the ICM - Middle front side of the block - Has a two wire connector on it, Yellow and Purple, usually twisted, that runs to the ICM. The sensor itself is in the block with just the connector showing outside the block. All years have this.
Ok
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Originally posted by phonedawgz:Oil Pressure sensor - Front side of the block - three wire sensor usually for a Fiero swap. This sensor threads in and is totally outside the block.
Ok
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Originally posted by phonedawgz:Evap Purge Solenoid - Might be right next to the throttle body inserted the intake manifold (96-97), might be bolted to the intake depending on the year. If external it might be located anywhere on a swap including the firewall or transmission. If inserted to the throttle body it has a single vacuum line connected to it. If not inserted, it has two vacuum lines to it. If you have a red connector, that is the Evap purge connector. The wires to it should be Green/White and Pink
Not in system.
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03:06 PM
Dennis LaGrua Member
Posts: 15143 From: Hillsborough, NJ U.S.A. Registered: May 2000
You can buy a cheap manual on eBay that should give you all of the info you want for the 3.4L DOHC engine. .Any manual for one of the following either new or used would have the info. Just match model years and you'll be OK. Applications: 1991–1994 Chevrolet Lumina Z34 and the Euro 3.4 sedan 1991–1996 Oldsmobile Cutlass Supreme 1991–1996 Pontiac Grand Prix 1995–1997 Chevrolet Monte Carlo Z34 1995–1997 Chevrolet Lumina LS 1997 Chevrolet Lumina LTZ
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
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03:50 PM
n7vrz Member
Posts: 521 From: Dixon Springs, TN Registered: Dec 2010
I have the Haynes manual for the '93 Lumina. The manual has pictures of the various installed engines with sensor locations for the engines EXCEPT for the 3.4 DOHC. That one engine isn't shown. Then there is this, the builder put the later, he said '97, intake manifold and fuel rail on the '93 engine. The upper intake manifold is positioned so that you can't get to the schrader valve on the fuel rail. The manifold is towards the rear of the engine/car and the valve is now under it. Makes it kinda hard to test for fuel pressure.
[This message has been edited by n7vrz (edited 08-19-2012).]
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07:25 PM
Aug 22nd, 2012
n7vrz Member
Posts: 521 From: Dixon Springs, TN Registered: Dec 2010
Found the air temp sensor. Pulled it out and took an ohms reading and it seems to be within proper range. Tried to take a rading on the coolant temp sensor and had a real hard time getting the probes in due to location and lines running where they are. Anyway, that reading was way out to lunch. So there's one item to replace. While I'm at the parts store I'm also going to get some extra ground straps to install. Might make a difference, might not. But I'll try it anyway.
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02:08 PM
aaronkoch Member
Posts: 1643 From: Spokane, WA Registered: Aug 2003
Fieroking may chime in on this, but when he first built his 3.4 TDC motor swap, it took him a while to find an issue that was preventing the engine from running properly. I think it ended up being something to do with the crank sensor, specifically the polarity, or that the wires weren't twisted / shielded enough. PM him for the details, but once he got that sorted out it ran like a raped ape.
Fieroking may chime in on this, but when he first built his 3.4 TDC motor swap, it took him a while to find an issue that was preventing the engine from running properly. I think it ended up being something to do with the crank sensor, specifically the polarity, or that the wires weren't twisted / shielded enough. PM him for the details, but once he got that sorted out it ran like a raped ape.
That was me too. I had extended the high resolution sensor wires, the one on the side of the crank case, and even though I followed the book/colors I ended up having them the wrong way around. 18 months to find that and 10 minutes to fix! Symptoms were that it idled great but was gutless under load and wold not go more than about 25 mpg. also kept throwing code 44's I think.
------------------ Anything I might say is probably worth what you paid for it, so treat it accordingly!
This engine is not gutless, revs perfectly fine, mpg's are a bit lower than I would've hoped. But I've been having to keep a foot on the gas at stops so it doesn't die. There may have been a little spirited driving thrown in also. It just wants to die when you come up to a stop and if you delay a shift. The rpm's just drop low enough that it can't keep going. It isn't just a sudden plummet off a cliff type drop. Just like at the bottom of a curve that is just a bit too low. Didn't get to the parts store today. I'll get the CTS and a couple of ground straps tomorrow and see if they make a difference.
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08:29 PM
ltlfrari Member
Posts: 5356 From: Wake Forest,NC,USA Registered: Jan 2002
If it's not throwing codes then just throwing new sensors at it is pointless, you may get lucky but then again I might win the lottery too!
Automajic or stick ?
For a stick you really need to hook up the clutch switch to D22 in the ECM. Also, are you running correct ECM and eprom program for the trans (stick or auto). You can fake the signals to an auto ECM/chip if in a stick and visa versa but if not, who knows what's going on?
Did you do this swap or buy it. If bought you need to check the basics first I think before just throwing sensors at it.If you did it then you know your setup, did you use 'wrong' part (ie ecm/chip trans combo).
------------------ Anything I might say is probably worth what you paid for it, so treat it accordingly!
I bought it. I took an ohm reading on the CTS and it doesn't match what it should be for the actual temp. Not even close. Mated to a 5 sp. Chip burned by Ryan at Sinister. ECM is from donor car according to builder. Whether the donor was stick or auto I don't know. I'm not just 'throwing sensors' at it either. I'm finding them and testing them first. Why I didn't have a code for the CTS is something else to check out. Once I've checked all the sensors for correct readings, I'll take the ECM and have it tested. After all that is done and everything checks out good then on to the tune in the chip. One problem I do have is finding the sensors. My Haynes manual doesn't show the 3.4DOHC engine so finding all the sensors is by eyeball and flashlight. Find something sticking out of something with a weather pack plug and go from there.
[This message has been edited by n7vrz (edited 08-22-2012).]
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10:17 PM
PFF
System Bot
ltlfrari Member
Posts: 5356 From: Wake Forest,NC,USA Registered: Jan 2002
Do you know or can you see the ECM number? Does not do any harm to check the obvious stuff. If it's mated to a stick, it needs a manual ecm but the symptoms don't sound to me like it's an ecm type issue and I know Ryan does good work, he did my chip for my swap. From your earlier description though, it sounds like it's having problems idling. I'm wondering if the IAC is stuck or out of phase with where the ECM thinks it is. I know there's an IAC reset procedure for the stock Fiero v6, wondering if the same might apply to this although I never had to do it on mine, might be worth a try, it's pretty simple to do on the stock v6, should be same on dohc. A search on here will probably find the description of how to do it.
Btw - If the ECM is adjusting the idle up and down (faster when cold, slower when warm) then your ECM and IAC are at least working. You can't take your ECM anywhere to have it tested. Only ICMs.
--- I most likely will get yelled at for this BUT you probably can solve this problem just by turning your throttle stop screw in a little farther. That will increase the minimum idle speed when the ECM has the IAC closed down. Just keep track of the turns so you can put it back if you end up manually bumping up the idle speed once the car is fully warmed up. The throttle stop screw looks like an old idle adjustment screw, is by the mechanism of your throttle crank, and will most likely have a cap over the screw so you can't see the head.
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11:29 PM
Aug 27th, 2012
n7vrz Member
Posts: 521 From: Dixon Springs, TN Registered: Dec 2010
Well, 'repairs' have come to a stop for a while. My sister has to move and doesn't have the money to do it. I'll get back to this as soon as I can but there's no telling when.