I am having some driveability issues with my 3.4 PR 5-speed swap. Codes are 32 and 45. Map sensor, TPS, IAC, and EGR valve have all been replaced. Motor has Accel 17 lb injectors, and Rodneys stainless vacuum lines, Darrell Morse Ported Throttle body and Intake, and 1.6 ratio roller tip rockers on a stock cam. I have not replaced the EGR solenoid, or the fuel pressure regulator. Distributor is original but module has been replaced. The engine has MSD ignintion wires, and an MSD coil. ECM is stock 88 with a stock chip.
Sometimes the idle stays high and comes down slowly when i pull up to a stop. More often when the weather is cold. In fact, on a long downhill grade I will get an SES light when the engine temp drops. It will go out as soon as the engine builds temp.
On occasion the engine acts like the gas pedal sticks, and stays at a higer RPM till I blip the throttle. I have checked the linkage and it does not bind up. The throttle body is clean inside and the throttle blade does not bind up. On other occasions the idle drops very low pulling up to a stop, or the engine may die out completely.
The engine has a bit of a rough idle compared to the 2.8. I remember driving new 3.4 Firebirds and they seemed to have a rougher idle too. Is that a characteristic of the 3.4's displacement?
Any recommendations on what to check are greately appreciated!
From the front page of Pennocks: Code 45 Oxygen Sensor - Rich Exhaust The ECM will set code 45 when the ECM detects a high voltage from the oxygen sensor, throttle is applied and the system is operating in Closed Loop (conditions must exist for longer than 50 seconds and engine must be running for at least 1 minute). Check the oxygen sensor and replace if necessary. Check fuel pressure. The system will go rich if the fuel pressure is too high. Check for rich injectors. Check for leaking injectors. Check for fuel contamination (specifically for contamination with oil). Check for proper ignition module shielding. If the ignition module is not properly shielded, the ECM might mistake the electro-magnetic interference for reference pulses, causing too much fuel to be delivered to the system. Check the canister purge for fuel. If full, check canister control and hoses. Check the MAP sensor. If the ECM detects a lower than normal vacuum then this will cause the system to go rich. Disconnect the MAP sensor. If the rich condition goes away, then a problem exists with the MAP sensor. Check for leaking fuel pressure regulator by checking the vacuum line to the regulator for fuel. Check TPS. An irregular TPS output will cause the system to go rich due to a false indication of accelerating.
If you're smelling a rich exhaust, definitely look at the injectors. There have been several PFF'ers that reported a rich condition with Accel injectors. That flow rate should be at 43.5 psi. If the regulator was working properly prior to the swap, no need to suspect it. It's exactly the same as the 3.4 regulator. You should get around 42-44 psi at the fuel rail at first key on/no start. After start and at normal idle rpm, you should be at about 38-40 psi. With engine off, you should be able to pull about 5 inches of vacuum on your pressure regulator and hold it for several minutes without leakdown. If it drops and you're sure you have a good vacuum, then the regulator is bad.
I would suspect some of the rubber fittings on the end of your lines may have a leak. I encountered that with Rodney's stainless lines when we used the old original connectors that were on the plastic lines. Look very closely at the little loop on the EGR solenoid. It only takes a very minor leak to set a code 32. Also be sure your metal tubes aren't bottomed out at the back of any L shaped fittings. It can block or severely restrict any vacuum.
How can you tell if the ignition module is properly shielded? Someone else told me I should pull my distributor to see if it is not sticking/ I change oil regularly but I guess the inner shaft can get gummed up.
My engine does run rich but only triggers the SES code when the temp drops. If I were to replace the Accel injectors which kind would be the best replacment what lb. injectors would be best to avoid running rich?
[This message has been edited by Rick 88 (edited 06-14-2014).]
17# injectors are the correct injectors for the 3.4 in stock form. The Fiero ECM doesn't always like the disk type injectors and usually will run rich as opposed to lean. I used Bosch injectors from a V8 BMW. They were modified pintel style injectors that I got from Fuel Injector Connection in Cumming, Ga. Rated at 17# at Fiero fuel pressure of 43.5 psi. One of our local guys just had his original Fiero 15# injectors rebuilt and flow matched and he was getting 16.2# which is a little lean for a 3.4, but probably within range that the ECM can bump up the flow as needed. An adjustable fuel pressure regulator may also be able to kick up the pressure. FIC can work with you and guide you for the correct injectors. They can also modify your original injectors to flow more. For the Camaro/Firebird 3.4 generating 160 hp, the recommended injector is 17#, which in reality is 16.666#. The folks at FIC are Fiero knowledgeable. http://www.fuelinjectorconnection.com/
There are some here on PFF that can guide you to the right Accel injectors if you wish to stay with them, or tell you how to fix that problem.
The SES light when coasting is probably the Code 32 EGR system. It will flash then go away. If the valve has been replaced, look toward the solenoid.
For the Rich burn, look at the Coolant Temperature Sensor located underneath the EGR solenoid and thermostat housing neck as being the culprit. If it senses a colder-than-actual coolant temperature, it will richen the mixture. Using the chart in this link and a multimeter, you can determine reasonable accuracy. http://www.gafiero.org/bbs/...=641.msg4644#msg4644
The distributor can't stick. It's a solid drive from the camshaft. It would certainly break something if the distributor offered any major resistance. I have read on this forum where some have had issues with module failure when using the hotter ignition coils, including some of the MSD models. The 2 wires inside the distributor from the pickup coil to the back of the module sometimes get pinched by the distributor cap or the plastic terminal of the pickup coil crumbles away. That might cause some interference or bad signals to the ECM.
[This message has been edited by fierofool (edited 06-14-2014).]
17# injectors are the correct injectors for the 3.4 in stock form. The Fiero ECM doesn't always like the disk type injectors and usually will run rich as opposed to lean. I used Bosch injectors from a V8 BMW. They were modified pintel style injectors that I got from Fuel Injector Connection in Cumming, Ga. Rated at 17# at Fiero fuel pressure of 43.5 psi. One of our local guys just had his original Fiero 15# injectors rebuilt and flow matched and he was getting 16.2# which is a little lean for a 3.4, but probably within range that the ECM can bump up the flow as needed. An adjustable fuel pressure regulator may also be able to kick up the pressure. FIC can work with you and guide you for the correct injectors. They can also modify your original injectors to flow more. For the Camaro/Firebird 3.4 generating 160 hp, the recommended injector is 17#, which in reality is 16.666#. The folks at FIC are Fiero knowledgeable. http://www.fuelinjectorconnection.com/
There are some here on PFF that can guide you to the right Accel injectors if you wish to stay with them, or tell you how to fix that problem.
The SES light when coasting is probably the Code 32 EGR system. It will flash then go away. If the valve has been replaced, look toward the solenoid.
For the Rich burn, look at the Coolant Temperature Sensor located underneath the EGR solenoid and thermostat housing neck as being the culprit. If it senses a colder-than-actual coolant temperature, it will richen the mixture. Using the chart in this link and a multimeter, you can determine reasonable accuracy. http://www.gafiero.org/bbs/...=641.msg4644#msg4644
The distributor can't stick. It's a solid drive from the camshaft. It would certainly break something if the distributor offered any major resistance. I have read on this forum where some have had issues with module failure when using the hotter ignition coils, including some of the MSD models. The 2 wires inside the distributor from the pickup coil to the back of the module sometimes get pinched by the distributor cap or the plastic terminal of the pickup coil crumbles away. That might cause some interference or bad signals to the ECM.
Thanks again for the tip on the injectors and all the other info. I assume the Accel injectors are disc type. i don't have any stock injectors to have rebuilt. I will contact fuel injector connection to see what they offer. Mustang V8 injectors are also 17 lb. but I don;t know if they are pintle style.
I will pull the EGR solenoid and inspect it. Paul Vargas sell rebuilt ones, Maybe it is time to replace. The coolant temp sensor has been replaced, but perhaps it is the wrong one. Does this sensor control the gauge? The temp gauge always about the quarter mark. Would that exaggerate the rich condition?
Thank you for the tip on the wires inside the distributor. That will be my next item to check. I did notice s pair of wires just outside the distributor that I believe have something to do with the tach that are not in the best of shape. Could these also affect driveability? Perhaps I should remove the MSD Coil and wires and replace with stock.
My car is driven almost daily. On the way back from work I got the Code 45 again. I had previously cleared all the codes to see it they would return. I must have driven about 15 miles before the SES light came on, and did feel a stumble just before this happened. The light stayed on all the way home. Based on how long it took to come on, would the problem is caused by a heat build up. What are things I should check to cure a Code 45?
The 302 Mustang injectors I used in the first of three 3.4's were 19#, not 17#. They ran rich, but not as rich as the 17# Rochester Multecs I used in the second 3.4. The Rochesters were stock for the Camaro/Firebird engine. The third 3.4 was when I contacted FIC and got the BMW injectors. They also run slightly rich, but have never set any codes.
The temp sensor you speak of in the corner of the head has no effect on the engine. It is only for the gauge and temp light. The CTS is underneath the EGR solenoid, positioned horizontally, pointing toward the passenger fender, and screws into the end of the lower intake manifold. It has an oval shaped plastic head. The one in the cylinder head has a round plastic head and has a split in the side of the plastic.
The temperature gauge should move to the 100 mark when you turn the key on. That's if the engine hasn't already been warmed up. The needle has probably slipped due to being pegged every time you start the engine. FieroSails.Com has a good article on how to fix the pegging temp gauge.
Whether or not you do the above wiring fix, you'll need to reposition the needle. To reposition the gauge's needle, you will need to remove the instrument pod, remove the instrument cluster from the instrument pod, and only at this point, remove the clear lens cover. That's because there are 2 hidden screws underneath the top of the instrument pod.
At that point you can see all the screws that hold the lens cover, so you don't break it. Grasp the round button of the temp gauge needle between your thumb and finger and pull hard. The needle will pop off. Turn on the ignition and plug in the harness on the left side of the cluster. You'll see the fuel gauge move to let you know you have power to the gauge. Now, position the needle at the 100 mark and press it back onto it's shaft. It will give you a little click as it snaps on. Reassemble.
The wires from the pickup coil to the ICM are long enough that they can get pinched under the back edge of the distributor cap. I like to twist the connector round and round. This winds the wires up and shortens them. Got that from another PFF member. I've also run a distributor for years with the harness connector completely broken off and just the wire terminals plugged onto the module. I slipped some shrink tubing over the terminals just in case there was enough voltage to arc between them. As for shielding the module? Don't know how you'd do it. It was never shielded from the factory.
I don't know which 2 wires you're talking about, but the tach filter wires run through the little cylindrical object bolted down below the stock coil location. It has a 2 wire plastic connector. I think they only affect the tach. One of my early cars connector had broken apart and unplugged and it didn't affect the engine.
Do a search on PFF for MSD or Blaster to see what you come up with in regards to issues in the Fiero. Include the entire thread in General Fiero and Tech archives. I had an MSD on my first Fiero back in 93 and the current owner still has it on the car today. Never knew of any problems it caused, but it's been a subject of problems with others on this forum.
Rick, I scored an EGR solenoid from Paul Vargas. It was money well spent. I recommend one of his highly.
I used the correct factory 17 MulitTeck's. I bought a refurbished set on EBay.
I was having this same problem when I did my 4.9 swap into my 88. I used my code scanner one day and saw that the ECM was seeing around -175* while the engine was doing this. I started wiggling wires on the engine till it stopped. It was the wiring to the CTS. I found some bad wiring there, and soldered in some new wires with heat shrink. That was the end of my problem. The ECM was dumping more gas to 'warm' the engine up. Like closing a choke so to speak.
If you have assess to a code scanner you can drive around with it connected and watch what your ECM is getting from the sensors.
[This message has been edited by josef644 (edited 06-16-2014).]
The third 3.4 was when I contacted FIC and got the BMW injectors. They also run slightly rich, but have never set any codes.
The temperature gauge should move to the 100 mark when you turn the key on. That's if the engine hasn't already been warmed up. The needle has probably slipped due to being pegged every time you start the engine. FieroSails.Com has a good article on how to fix the pegging temp gauge.
Whether or not you do the above wiring fix, you'll need to reposition the needle. To reposition the gauge's needle, you will need to remove the instrument pod, remove the instrument cluster from the instrument pod, and only at this point, remove the clear lens cover. That's because there are 2 hidden screws underneath the top of the instrument pod.
At that point you can see all the screws that hold the lens cover, so you don't break it. Grasp the round button of the temp gauge needle between your thumb and finger and pull hard. The needle will pop off. Turn on the ignition and plug in the harness on the left side of the cluster. You'll see the fuel gauge move to let you know you have power to the gauge. Now, position the needle at the 100 mark and press it back onto it's shaft. It will give you a little click as it snaps on. Reassemble.
The wires from the pickup coil to the ICM are long enough that they can get pinched under the back edge of the distributor cap. I like to twist the connector round and round. This winds the wires up and shortens them. Got that from another PFF member. I've also run a distributor for years with the harness connector completely broken off and just the wire terminals plugged onto the module. I slipped some shrink tubing over the terminals just in case there was enough voltage to arc between them. As for shielding the module? Don't know how you'd do it. It was never shielded from the factory.
I don't know which 2 wires you're talking about, but the tach filter wires run through the little cylindrical object bolted down below the stock coil location. It has a 2 wire plastic connector. I think they only affect the tach. One of my early cars connector had broken apart and unplugged and it didn't affect the engine.
Do a search on PFF for MSD or Blaster to see what you come up with in regards to issues in the Fiero. Include the entire thread in General Fiero and Tech archives. I had an MSD on my first Fiero back in 93 and the current owner still has it on the car today. Never knew of any problems it caused, but it's been a subject of problems with others on this forum.
Do the BMW injectors require any modifications to the wiring, or need a special 0 ring?
I don't recall seeing my temp gauge pegging on my Fiero when I start it. I will check when I go home today. Perhaps the original owner fixed the pegging issue but never re adjusted the temp needle.
I will also check the distributor wiring. I think someone here makes a replacement harness for the distributor. The wiring I mentioned were those going to the tach filter. I want to repair or replace these before they break. and the tachometer quits completely.
The injectors I have will drop right in and plug to your harness. I'm sorry that I don't have the part number. When looking at the bottom, you will see a disk with 3 or 4 holes, but they are a modified pintle style. John at FIC will know what they are. Let them guide you.
With some injectors, the lock rings can't be used with the Fiero fuel rail. As long as the injector is the same length, you don't need them. The injectors are captured between the rail and the lower intake manifold and won't go anywhere until you blow the top off the engine.
