OK, i had my trans redone, and the guy called and said that when he went to test drive the car it back fired as soon as he rolled in the gas. Anyway my wife drove it home, and i looked at it when i got in. It was idleing funny, so i found vacum hose blown off, then i notice it still showed low 02 reading at idle, i found the MAF screen was blown out, broke MAF getting it off, got new one today. Car never backfired until tonight! i notice it was falling on it's face at part throttle, and 02s were low then (POW) think i blew the other manifold out. Any way i will check the wires behind the coil pack in the AM, but does it sound like my fuel pump is going out? I dont have the hood mounted kind, so i cany check going down the road, how can i check pump? Oh what does code 42 mean? The car had no popping issue before, but ive had a hard time getting good fuel at WOT.
Code 42
- Thread starter 1chance
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Sorry, i meant Exht manifold gasket. Im about to start looking for the problem, i was thinking he may have caught a wire between the trans, and engine. I dont see any, and thanks for the link, it say ESC could be bad, that's the coil pack right? How can i check it?
It really sounds to me like the new MAF could be bad. When I blew out a header gasket at the track, the car still ran ok, just was louder. When my fuel pump went bad, the car leaned out at the track, but ran fine otherwise. When my coil pack went bad, the car sputtered at WOT. MAF sensors are notorius for going bad, and supposedly even new (rebuilt) ones are a crap shoot. Best fix for a bad MAF is the translator set up from Full Throttle. The chart I refered you to on gnttype.org talks about the ignition module (or a wire to it) being bad, thus code 42. It also says the chip in the ecm might not be seated properly. I think I would also try reseating the chip and see if that helps. If you have a scan tool, see what the MAF reading is at idle. Should be something like 4-6 Grams/sec. You might have been reading code 43 on the chart. Here is what it says about code 42:
CODE 42
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.
During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.
An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.
The conditions for setting this code are:
System in BYPASS mode but the ignition module is still controlling timing
- or -
Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.
Typical causes for this code include:
1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM
CODE 42
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system.
During cranking, the timing is controlled by the ignition module while the ECM monitors the engine speed. When the engine speed exceeds 400 RPM, the ECM sends a BYPASS signal to the ignition module which switches the timing to ECM control. The ECM calculates what the timing should be then "tells" the ignition module via the EST circuit.
An open or ground in the EST circuit will stall the engine and set a Code 42. The engine can be re-started but it will run on ignition module timing.
The conditions for setting this code are:
System in BYPASS mode but the ignition module is still controlling timing
- or -
Engine speed > 600 RPM with no EST pulses (ECM controlled timing) going to the ignition module for 200 msec.
Typical causes for this code include:
1) BYPASS line is open or grounded
2) EST line is open or grounded
3) PROM or CALPACK not seated properly in the ECM
4) Poor connections between ignition module and ECM
5) Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise)
6) Faulty or incorrect ignition module
7) Faulty ECM
OK, but it wasn't doing any of this before it went to the trans shop. I dont see any broke wires, ill look again when car cools. The MAF seems to read fine 4-6 at idle, the car shut off last time, but started right back up. I know i had another chip made (TT), but it did it with old chip, my car cant seem to get enough fuel at WOT, ive added dual alky, and had the chip redone. It does'nt do it everytime, just seem to backfire when it get's hot! Im trying not to throw part's at is, i would like to fix it the frist time. Code 42 means coil pack? Then do you think fuel pump is bad?
If you think the MAF is good, then other causes of a backfire could be the TPS sensor or the crank sensor. If you don't want to throw money at it blindly, check the tps readings when it backfires. See if there is a drop out at 0 volts and then picks up again. As for the crank sensor, I don't know how to trouble shoot that. I have read that the crank sensor can cause a back fire. Code 42 is not the coil pack as far as i can tell. Seems to be ignition module. why do you keep thinking it is the coil pack? Also reseat the chip and see if that helps. You might want to duct tape a fuel pressure gauge to the windshield and drive it, to diagnose the fuel pump. I bought my gauge from Caspers website. Let us know. good luck!
Well i changed the spark plugs, and put on a fuel filter. The car has not misfired yet. I notice that O2s drop way down(440) at about 3/4 throttle, so would that indicate a bad FP? Also at times the O2s are very low at idle like090-060, but once it goes up to 800s it idles good. I was thinking the O2s drop like that because im not pressing any farther on the gas. Ok so the ESC is not in the coil pack? Where is the ignition module?
TURBOELKY
Well-Known Member
- Joined
- Jun 27, 2005
- Messages
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I once washed my engine with water, what a mistake! I had error code 42 for 3 weeks, drove me nuts!!!! I tried a different ecm, maf, coil pack, EVERYTHING!!! (besides a new engine). I looked up the code on here, tried everything all recommended, to no results. Ended up putting a direct ground to my coil pack mounting plate, and it went away. May have just been a coincidence and something took 3 weeks to dry out
or it worked. I tried a different translator, man, It flustered me!!! I'm now paranoid about ever getting code 42 again!!
If they had the tranny out, maybe they pulled a ground out of its loop on accident near the back of the head? The 42 will cause the car to pop 100% if you get on it. Your popping problem is being cause by the plague code 42....muaaaahhaaaaaaahhhaaaaa. couldn't resist, sorry.
the ignition module is under the coil pack.
or it worked. I tried a different translator, man, It flustered me!!! I'm now paranoid about ever getting code 42 again!! If they had the tranny out, maybe they pulled a ground out of its loop on accident near the back of the head? The 42 will cause the car to pop 100% if you get on it. Your popping problem is being cause by the plague code 42....muaaaahhaaaaaaahhhaaaaa. couldn't resist, sorry.the ignition module is under the coil pack.
Well i hooked up my Direct Scan, and this is what it showed just be fore it backfired! I have a (TT) chip, and timing is supposed to be 23/21. I rolled into the gas, and at 37mph/3600 rpm/TPS 3.08/LV8=255/IAC=111/ INJ-PW 12.65/Boost 94%/Spark Adv=18.6/KR=0 then went it=5/AF ratio=11.7/O2=55. After that BOOM! Now before that 02s came down from 830-640-441-173 then55. MAF went as high as 193-188. So tel me what is wrong! Fuel pump? Also shouldnt timing be at 23? not 18.6, or was it trying to save engine?
I have a (TT) chip, and timing is supposed to be 23/21. I rolled into the gas, and at 37mph/3600 rpm/TPS 3.08/LV8=255/IAC=111/ INJ-PW 12.65/Boost 94%/Spark Adv=18.6/KR=0 then went it=5/AF ratio=11.7/O2=55. After that BOOM! Now before that 02s came down from 830-640-441-173 then55. MAF went as high as 193-188. So tel me what is wrong! Fuel pump? Also shouldnt timing be at 23? not 18.6, or was it trying to save engine?
TURBOELKY
Well-Known Member
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- Jun 27, 2005
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- 3,474
is this all happening while showing error code 42??? or has that been resolved?
Well i hooked up my Direct Scan, and this is what it showed just be fore it backfired!
If you have checked the TPS voltage for no drop outs, then we can rule out a bad TPS sensor. Eric's website says LV8 and MAF should lock on to 255 at WOT. Looks like if LV8 hit 255 then you might have done more than just "rolled into the gas". Anyway, maybe your MAF is bad? Maybe still a bad crank sensor? If it is the fuel pump, you can blow a HG so you really should get a fuel pressure gauge and check it!
OK, thanks. I notice that when i was driving it this morn that the timomg, or spark advance went to 41 any time i gave a little gas! Will the crank sensor cause that, or the ignition module is malfuctioning? It did give a Code 42, so i notice the ignition module was very hot!
When my crank sensor went bad,it would start when cold than after it got hot
15 minuts later it would mis fire like off timing than shut off and not run until
it cooled down 1 hour latter.It would repeat this till I changed it.It would do it
while on the road not Idling in park.
15 minuts later it would mis fire like off timing than shut off and not run until
it cooled down 1 hour latter.It would repeat this till I changed it.It would do it
while on the road not Idling in park.
Dang! Did i order the wrong part? The ESC is the box on the pass fender? I thought the ignition module under the coil pack control the spark? The code 42 is talking about the sensor on the fender, or the module under the coil? What is (EST) i dont know what that does.
salvageV6
Daily Driver
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- May 25, 2001
- Messages
- 20,992
You want an IGN module under the coil pack.
ESC is the knock sensor filter conditioner that sends the ECM KR data over on the passenger fender it rarely goes bad ever.
Code 42 can be the module under the coil pack.
I would get a can of electronics cleaner, plastic safe, and spray the module connector and existing module pins after unbolting the connector from the side of it.
Also do the same thing at the ECM with those connectors.
Many code 42's are bad connections between the module and the ECM.
ESC is the knock sensor filter conditioner that sends the ECM KR data over on the passenger fender it rarely goes bad ever.
Code 42 can be the module under the coil pack.
I would get a can of electronics cleaner, plastic safe, and spray the module connector and existing module pins after unbolting the connector from the side of it.
Also do the same thing at the ECM with those connectors.
Many code 42's are bad connections between the module and the ECM.
