Hey Guys, Still enjoying the car! Hope Pap had a good time in the US. For the last few weeks I have been getting the slow down light (5/8). The light comes on sporatically during warmup (flickers) then goes off. During driving it flickers sporatically and or goes solid. When it goes solid, sometime is feels like it okay othertimes it feels like I have lost power, sometimes it feels like I have lost power even without the Slow down light coming on. I switched the Ecu's, same problem on 5/8. I noticed the outer sleeve on the thermocouble cable towards the connection was missing and exposed the two wires (which look like they are bare without any sleeve separating each). After looking at the cable closely, the outer sleeve had slipped off so I pulled it back over the two wires. I plan to drive the car tomorrow to see if the problem continues, any other tests I should perform. Can I switch the thermocouple cable to the other side to see if it is the problem. Thanks Vishal
For safety, you'd be well-served to buy a $20 laser thermometer to shine at the cat on your problem side to insure that your temps are below 400 F during idle or light driving, or below 800F while tracking the car hard. In other words, are you getting a real alarm to SLOW DOWN or is it a false alarm. Swapping each exhaust ecu from the left side to right side of engine and vice versa is a good free test. Hooking up your ohmeter to measure the resistance between pins #1 and 6 (extreme ends) on each MAF under the black MAF data cable (with engine off) is another good test to perform early.
I have this same 5-8 problems and I have seen several others in the past year post the same problem. Seems to be a somewhat common problem on the 348 and someday maybe someone will figure out why it happens. Rodney Dickman 1990 348 TS
It can happen for a lot of reasons; obstructed cat, failing cat ECU, bad O2 sensor, misfire, bad plug wires, dirty/corroded electrical connections, etc. etc. No Doubt's web site has a great section on pulling ECU codes which helps to quickly pinpoint the underlying cause(s).
Thanks for the feedback so far. Took the car out today,no slow down lights, however the check engine 5/8 came on once and stayed solid, shut the car off and it still came back on. It went off after 2 minutes.
Hey Guys! I pulled the codes, and cross checked with the club348.com site (great site by the way). I drove the car today and the check engine 5/8 light came on and went off after a minute. I also got 5/8 slow down light. I initially posted that the car some giving the slow down light on the 5/8 side and after switching the same condition occured. I mistated this as initially the 1/4 slow down light came on, and when I switched the ecu's it looks like now I am getting the 5/8 warning light. 5/8 error code 4112 - stroke sensor\phase sensor error code 4121 - Cat temp Ecu error code 1212 - (Lambda reultr intake manifold compensaton (Maf or o2 sensor) error code 1212 - (O2 sensors) error code 111 (Hot wire Air flow meter -Maf sensor) 1/4 error code 4121 - Cat temp Ecu error code 4122 - (Cat temp too high) error code 4112 - stroke sensor\phase sensor error code 1212 - (Lambda reultr intake manifold compensaton (Maf or o2 sensor) error code 1212 - (O2 sensors) error code 1111 - (Maf) error code 111 (Hot wire Air flow meter -Maf sensor) Please help. 1. What would be the best course of action? 2. I looked at the club348 website and changing some of the above parts does not seem too complicated. Please advise on which parts need to be replaced, the best place to buy them from at a decent price and what the corresponding parts numbers would be. Ie: O2 sensor (i see there is a 2 wire versus 4 wire, etc which one should I get, I am handy however would prefer to get the job simple ie:no splicing of wires if can be avoided with the correct part, etc... Or should i just get the car serviced at the shop. Everytime I go to the shop I get a bill of at lest 2k If I can learn something I would love to fix it on my own! Thanks Again, V
That's quite a few codes! Is the car new to you and came with all of these error codes or are the error codes a sudden new appearance? Let's do some basics before we go buying new parts to see if we can eliminate some of those error codes for free. First, look at all of the junctions/intersections of your two u-tube black plastic air tubing on top of your engine. Do you see any obvious gaps that could let in unmetered air? If so, correct the gaps. Now, open up your air filter box. Inspect your air filter for oil or excess debris. With the air filter off, look down into your MAFs with a flashlight to see if there is any oil or obvious debris further up the intake. Clean the air filter. Put it back in. Screw down the air filter box. Next, use your ohmmeter to measure your MAF resistance in both MAFS. Post the resistance measurement for both MAFs here. Now set both MAFS to 383 ohms. Here's how: http://www.club348.com/technical/Tech/348.html#AFMixture Buy some electrical contact cleaner and Stabilant 22a. You're going to want to coat every data connection and ground that you can find on your car. Reset your main ECUs. Here's how: http://www.club348.com/technical/Tech/348.html#resetECU After the reset process is over, go drive your 348 for 20 minutes. Even if your Check Engine Lights are off, pull your codes again and post them here.
Hello No Doubt, Thanks for the feedback, below are the answers to your questions. 1. Is the car new to you and came with all of these error codes or are the error codes a sudden new appearance? I have had the car since sep of last year, it has been to the shop a few times for different errors,the last time it was in was for tire change, prior to that a 5/8 ecu and minor oil change. I replaced the 1/4 ecu a few months ago as well. 2. "First, look at all of the junctions/intersections of your two u-tube black plastic air tubing on top of your engine. Do you see any obvious gaps that could let in unmetered air?" I found the left air tube was not connected the vent. I have fixed that. 3. "Now, open up your air filter box. Inspect your air filter for oil or excess debris. With the air filter off, look down into your MAFs with a flashlight to see if there is any oil or obvious debris further up the intake. Clean the air filter. Put it back in. Screw down the air filter box. No visible debre, cleaned the air filter and put it back. 4. "Next, use your ohmmeter to measure your MAF resistance in both MAFS. Post the resistance measurement for both MAFs here." Having some trouble here, its been a while since I used a multimeter, I have selected the ohm setting, however am not getting a reading. The mm works I tested a (aaa) battery, etc... To test the Maf, I disconnected the cable, put the test leads on 1 and 6, I tried reversing them as well. The work was not on or started. 5. Buy some electrical contact cleaner and Stabilant 22a. You're going to want to coat every data connection and ground that you can find on your car. Will do Thanks Vishal
Hello No Doubt, I got the Maf reading, . 5/8 ---387 1/4 ---382 Based on what I have reading they need to be identical, so I will reset them to the factory 383, unless you recommend otherwise. Thanks V
Nice work, Vishal. You still need to shoot a laser onto your cats to take their temp after a hot drive (go to Harbor Freight or COSTCO or Wal-Mart...they're about $20). You want to do that to insure that you don't have a true overheating problem (fire danger!). Also, reset your main ECUs. Here's how: http://www.club348.com/technical/Tech/348.html#resetECU After the reset process is over, go drive your 348 for 20 minutes. Even if your Check Engine Lights are off, pull your codes again and post them here. The codes that you get now will have more meaning because you've fixed the air gap and reset the computers.
Hello No Doubt, It only took me a few months to get around to the below so finally today, I rechecked the codes as advised by you. Here is the breakdown. Every time I went out to check the car I ended up taking it out for a short ride (2 hours later I would return 5/8 4121 4122 1111 1/4 4121 1111 I will stop by radioshack and pick up a laser thermometer as advised. FYI - I have noticed the 5/8 light comes on a few minutes after I start the car and also when I drive. Thanks Vishal
