Reply With QuoteI don't jump start 24 to 12 any more, I blew a relay on a Geologists hire navara one day, we were about 500km from the middle of nowhere and I can't sort it out in my head where to put the leads to make a 24 volt system 12 volts. 100% gun shy now.
Indeed. We are making a 'test rig' to test the modules, then if the modules test OK only the wiring or coils can be bad. So goes the theory.Originally Posted by shocker1
Bad batch of Denso stuff, eh? Very strange! Denso quality control and parts are normally top-notch.The coils were Toyota, found out today that the new ones they sent to replace the defects came from another dealer. The original Parts dept did not have anymore, maybe a bad run because the parts guy acted like it was expected.
Speaking of dealers, I recently fixed a Toyota Prado that had been 'written off' by a dealer service dept- they told the customer that every computer, etc. in the vehicle was stuffed (a result of the car being jump-started with 24volts instead of 12V). Anyway... the car ends up at my workshop. I poke around with my meter and lo and behold one 12V supply to the engine ecu was missing. Turns out all that was stuffed was the EFI relay.
Stupid full-o-fail dealership.
The customer was really happy that I fixed it but really pi$$ed off at the other guys for misdiagnosing a very simple fault.
I don't jump start 24 to 12 any more, I blew a relay on a Geologists hire navara one day, we were about 500km from the middle of nowhere and I can't sort it out in my head where to put the leads to make a 24 volt system 12 volts. 100% gun shy now.
If you put the negative lead onto the chassis of the 24V truck and the positive lead to the jumper between the batteries (giving 12V) I can't see any problems at all. There are other ways of doing it too, but I'd best not tell you or risk confusing you before your morning coffee has done its work.
I agree, Denso has some super parts. They have expanded into the aftermarket to include, AC, starters and alternators for many makes. As well as electrical components. I buy Denso or AC Delco, none of that Cardone crap in my shop.
I have been wondering about those coils too. Something fishy there. Maybe something happened shipping or warehousing. Like a lightning strike!HAHAHA
Digs jump the first battery in the series.
93 Nissan Altima, backfiring and sputtering once it warms up. Runs fine at cold. We figured it was a water in gas problem from runnin it below half tank in freezing temperatures, so added gasline antifreeze and topped it up. Problem has been alleviated somewhat but is now doing it once the engine warms up. The fuel filter is on the firewall in the engine compartment and I'm wondering if it would act as a trap for the water, unthawing it 20ish minutes or so after cold start and warmed up. Any guesses otherwise?
If the problem is after it warms up it most likely not an ice problem. If it were starving for fuel due to freezing up it would do it more cold. Gasoline antifreeze/water remover is nothing more than alcohol. This would explain the change you experienced in how it ran warm after you added it.
In my mind I am thinking coolant temp sensor, O2 sensor or maybe even a distributor. Try unplugging the coolant temp sensor when it acts up, if that does not work unplug the O2. Next component would be the mass air flow sensor located near the air filter in the intake duct. Unplug this too and if it clears up that could be the issue. It would really be great to know it the PCM has stored any codes, it may have even if the check engine light is not on.
These vehicles are known for distributor failures. Does the car have a tach? If it does is the tach needle jumping around? They have an optical sensor inside that is very delicate and really crap.
Another possibility that I have ran into on these cars is a bad intake gasket. I have seen them only act up warm. Get a can of carb cleaner and when it acts up spray around the intake. Take care not to spray a whole lot because there is a fire hazard doing this. If it is a vacuum leak it will run much better when the cleaner gets sucked into the intake. If that happens you can pinpoint it with the spray. Vacuum leaks in other places can cause the same thing as well.
This is for wagon.
2003 Chevy K1500HD truck, codes P0120 and P2135. This is for the Throttle Actuation System(drive by wire) P2135 is a TP sensors 1 and 2 correlation. Used labscope to check the signals from the TPS's, TPS 1 had a proper signal with no drop outs, TPS 2 had a square wave riding on the signal. The Voltage matched TPS 1 but the square wave measurement showed it was going from 0vdc to the voltage reading relative to throttle position. Well we have two other trucks like this at the shop and they all have this on TP2. The 5vdc supply to the sensor from the TAC module is steady on TP1 and on TP2 it is a Ovdc to 5vdc square wave. This is not a problem but it seems odd to have a modulated reference voltage to a TPS. No mention of this signal being modulated in the circuit description of the TAC system operation.
The truck has not acted up yet and has not reset the codes. So I will update you with what I find tomorrow. Just thought the idea of a modulated TPS 5vdc reference would make a good conversation subject. Thoughts?
BTW P0120 is TPS 1 circuit fail, it is probably going to be a throttle body but gotta verify before repairs.
All great places to start looking, its been awhile since I pulled any wrench so I thought it best to ask. I also forgot to mention its EFI, my apologies(Also no tach) I was wondering about the O2 sensor and MAF problems as well - my first thought was perhaps O2 but wasn't sure. I just asked the GF if she notices any funny smells in the car when its acting up and she says yes, sulfurish
so I am thinking the O2 on the cat is a likely candidate.
I've got a Chilton somewhere here I'll dig out and see where I can unplug that sensor without getting burned.The GF hasnt reported any Check Engine lights either but as you mentioned that doesn't mean much and I would bet there are indeed error codes stored.
I'll definitely try some of the other suggestions too after checking the O2. Thanks for getting me pointed in the right direction, very much appreciated!
Maybe they do that weirdo thing with the square wave to get around occasional noise issues from spark plugs, power lines, etc. It most likely uses both as a fail-safe arrangement and ignores one if its signal looks no good. I always wonder what is wrong with a normal throttle cable setup... much simpler.
Could be but the TPS's are in the same place inside the throttle actuator. I hate this drive by wire, if it fails it has no power or shuts off completely. The benefits are PCM management of throttle angle during shifting. Guess that could help tranny life but damn. The electric power steering assist on the new Cobalts is another deal that caused big problems on those electric buses i used to build. Now a big problem in a Cobalt. Why fix what is not broke I always say.
No problem. There could also be some exhaust restriction(converter) as that would cause the symptoms you described. Just a matter of elimination of the basics and working back. If you can get the codes read it would greatly help your diagnosis and save loads of time.All great places to start looking, its been awhile since I pulled any wrench so I thought it best to ask. I also forgot to mention its EFI, my apologies
I'll definitely try some of the other suggestions too after checking the O2. Thanks for getting me pointed in the right direction, very much appreciated!
Hmm, that car was rear-ended hard enough to shear off the muffler hanger last year, apparently they tacked a new one on or something when they fixed the bumper. I should give it a visual inspection. As for a code reader, I've been debating buying one, because the car is getting on in age...assuming they arent too pricey. Would save a lot of time and money if/when something goes wrong for sure. Thanks again
Fade, I've had a few cars act similar to yours, and it was a plugged up converter. It had the same sulfur smell and sputtering problems. I removed the catalytic converter (this was a '94 3.8 Pontiac Bonneville btw) and the car ran great, but loud..so i took a long screwdriver and made some "vent holes" through the honeycomb in the converter, it helped and technically it was still legal in the eyes of the inspection station.(Might not be in a smog test though.) Just something to keep in mind.
Update on the EDIS issues... we made a test rig and tonight we had plenty of sparks using proper EDIS coils. So, that leaves wiring or the Hyundai Excel coil packs. We will soon find out - I'll keep you all posted.
I am betting on the coils.
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