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Discussion Starter #1
Ok. I have a 1995 caprice, I've had issues with the car hard starting.and when I do get it to start the car pops and backfires. But once I get the car going things are fine. I put an OBD1 tool on the car and got 3codes: 18, 32, 36. What are these codes and. What do I need to do to fix the issues...I was doing highway driving and the car cut off. VERY SCary!!
 

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Code 18 is injector driver detected wrong voltage to injectors for 4 seconds at one point in time. 32 is the egr code, and 36 is the opti low resolution code. Theres a possibility that the 18 and 36 are related, possibly due to when the pcm is getting wacky high res pulses, it also caused the pcm to fire the injectors in a manner that could trip the code 18 (possibly during cranking). If it was just code 18 w/o 36, i would say check the injector connections and wiring, or suspect a bad injector, but since its dieing on you and you are getting code 36, i would bank on it either being the optical sensor, or the opti electrical harness. Try reseting the pcm, and starting it. Once its running, take a long screwdriver and lightly press on the electrical plug going into the opti. Dont press hard, just enough to barely wiggle the plug. If the car reacts to this, its the opti harness causing the hard starting and stalling. If not, check the entire length of the opti electrical harness, and if its not chewed or mangled, its probably opti time. Also, after performing the tests, pull the codes again just to see if the code 18 comes back. Troubleshooting the egr code 32 is pulling the vacuum line off the egr, and pushing the valve diaphram in and putting your finger over the vacuum port to see if the diaphram will hold open. If it dont, replace the valve.
 

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^Edit to above post, the first time i said code 36 is the low res. code. I meant Code 36 is the opti HIGH res code. Sorry for double post, but i cant edit right now!
 

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Discussion Starter #5 (Edited)
I apologize it was code 16, 32, 36, 48 not 18. I had the codes checked and from there I don't know what I need to do now. Basically code 32 was EGR valve, and 48 was MAF I believe. But code 16 I'm lost as to what I need to do can someone explain from there. DiGGM95, I have changed my Opti twice now so I'm seriously hoping that that's not the issue...because if so I'll probably be looking to sell my car if that's the problem. I also had the PCM reset and I changed the MAF, EGR and the car still shutoff but not CEL??
 

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That code 16 instead of 18 unfortunately points to the opti, or a bad connection to the optical sensor. Code 16 is the worse of the two opti codes, as 16 is loss of the low resolution signal. The low res. signal fires the ignition, and the high res. is the injector signal. If you lose the high res. signal, the car will still run once code 36 is set. The car has no backup for losing the low res. signal, and once it goes, the car will die and wont restart until the pcm can get a clean signal again (it gets spooky when getting code 16, you never know when its going to shut off or restart, its extremely random). Since you have already did the opti twice, make sure the 4 connector slots in the bottom of the opti electrical harness plug on the opti side are not corroded, or the springs in each slot smashed flat. While you got the electrical harness unplugged, unhook the other end of it from the plug on the pass. side of the intake and take an ohm meter and verify its got good continuity through the harness, shaking the wires around while testing the harness. Check for any oil dripping from behind the opti. Leaky seals will finish off an opti in short order. Check the grounds on the drivers side head, check the aux. battery post for corrosion/melting, and check the pcm connector plugs to make sure they are plugged in securely. The MAF usualy will show faults when bumped directly on top of it, usualy causing a stumble.
 

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Discussion Starter #7
So basically I'm screwed? Crap....well I sprayed brake cleaner in the plug harness as well as the opti and let dryfor about 15min. Then I reconnected and then the car started and ran fine for a while and once again shut off. Now when u say disconnect both ends of the opti connection are you speaking up along the intake? If so can I just replace that connection? Last question for now, if the wire isn't the issue are you saying its my opti or what?
 

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Yes, the harness disconnects about half-way back on the intake. There are a few guys on the forum that make the harness, Gary is one of them. There is a link to a site that sells them that was just posted in a thread in this section (id copy and paste it, but i currently lack that ability, MarkoSS (sp.?) is the thread starter), or try rms autoparts online. Imho, if you are getting code 16 and 36, there is a problem with the pcm recieving the optical sensor pulses, whether it be a bad connection in the electrical harness, oil contamination in the opti, or a bum optical sensor (i would doubt that the os has simpily failed, but its not unheard of). The opti thats on it now is a delco opti?
 

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Discussion Starter #10
Yes its a delco opti and I will disconnect that wire and clean it really good and also check to see if the wiresare corroided....I'm hoping this is the issue, because if not then I'm gonna have to send it back to the shop and have them redo the opti . Well how much does the parts lady sell opti's for...just incase? Let's just say this opti is bad as well...where should I turn to from here, because clearly I've replaced a few on this car in less then 100k ?
 

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My car would do what you are describing, and it was my Opti Electrical Harness. If i touched the plug in the opti with a screwdriver, the car would die instantly. I managed to save mine by taking a stick pin and bending the four little retension springs back out in the bottom of the plug, and im ok for now, but no doubt i plan on getting a new harness after the first of the year. Thepartsladi sells the delco/delphi opti's for $250 + shipping. Also, did you check the Opti Vent Harness to make sure it draws vacuum with the "small piece of paper on the blue elbow" test? Most people get a new OVH assembly when they get a new opti for cheap insurance against early failure due to condenstation not being evacuated (opti will NOT survive for long without the OVH functioning). Make sure that you get the timing cover seals checked for leakage as well, as i myself have had more issues with oil killing opti's than i have water. If the seals for the WP or opti are seeping, you wont keep any brand of opti alive on it for long.
 

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Discussion Starter #12
Yes I checked the vac at the vent for the opti I used a blue latex glove and the suction stuck pretty well, but I guess tomorrow I will check the wiring harness and see if I can bend those pins slightlyand pray that that's all it is. But hopefully its something that simple b/c with it being xmas idt many shops will have my car availble until after xmas....so that's gonna suck. But wish me luck and I will let you know what happens tomorrow.
 

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Discussion Starter #13
Ok so today I looked over the opti harness and saw that near where it connects to the actual opti the wires were a little corroided and worn. So maybe that's causing my car to die. So I went to the junkyard and snatched up 3 harnesses. I installed the replacement and its running ok so far.....any other tips I could do to see if there are any issues?
 

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Ok so today I looked over the opti harness and saw that near where it connects to the actual opti the wires were a little corroided and worn. So maybe that's causing my car to die. So I went to the junkyard and snatched up 3 harnesses. I installed the replacement and its running ok so far.....any other tips I could do to see if there are any issues?
Since its doing ok now, It was the harness causing the code 16, 36, and the dieing and hard starting. I learned the hard way about the harness, by pulling my opti 3 times before realizing to check it. Anytime you get opti problems, unless there is an obvious cause for them, always check the harness before doing the opti. As for the MAF code 48, before changing the MAF out, check the wiring at the plug for it, as they also are known for breaking inside the insulation. If you are still getting code 48, the car is running in speed density, and the MAF is either dead, or theres a short to it somewhere. Anyways, glad to hear you got the biggest problem fixed, now your car won't have to sit in the shop over Christmas! Btw, that reminds me, have a Merry Christmas, and Happy New Year!
 

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Discussion Starter #15 (Edited)
Ok have a merry xmas as well. Guess what?? Well I was driving tonight and everything was fine until I heard and felt the car was bogging down almost shutting off but I tapped on thre gas it stopped but then continued...now I'm really lost. I've changed:2 opti & rotors ,EGR valve, MAF, fuel filter, I'm about 1,300miles away from needing an oil change,I changed the harness on the opti, I sprayed the throttle body w/ carb cleaner, used Lucas, seafoam, had new plugs and wires 3 oil changes ago no CEL, and I even up graded to premium gas the last 3 times I've filled up.....WTF is it?
 

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Discussion Starter #17
Yea no codes, so I guess that's next....uhmmm so fuel pressure with key in on pos. (But not started) should be around 38-41? Or higher and with car running and in drive should be 36-up ? Correct?
 

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I like to see at least 40-47 psi with the key on and motor not running. It can drop up to 10 psi from the key on reading once the motor is cranked, but should rise back towards that inital reading as the throttle is mashed to WOT when on a test run with the fuel psi gauge taped up to the windshield.
 

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Discussion Starter #19
Ok so I went ahead replaced the Fuel Pump, Strainer, Wiring harness, and I even put on a Coolant Temperature Sensor, and the Car still does the same thing....once I completed it, I turned the key to the on position to allow the Pump to cycle a few times before I started it. then I cranked it and the car cranked fine I even had more power when it cranked.
So I let the car warmup for about 20-30min. before I road tested it, because the temperature where I'm at is 15 Deg. the car Idled fine the entire time.....but I got in it and decided to test it out, No Reving it up and gunning it, just normal driving, I never went faster then 35MPH's I drove 1 block and it died.....and then I restarted it and turned the car around.....and it died again....then it became harder and harder to restart it....so when I finally got it home I let it idle again and it seemed fine.....what could the problem be now?

I will run down all the things again that I've done to it:

Yesterday - Fuel Pump, Strainer, Wiring Harness
within 2yrs...3-4 Mo. ago - 2 opti sparks ( Both Put on by a shop)
3-4 Mo. ago - adjusted the timing ( the shop )
4 mo. ago - Coil
6,000 miles ago - plugs and wires
due in 500 miles - oil change
2 wks ago - EGR Valve
2 wks ago - MAF sensor
1 wk ago - Fuel Filter
2 days ago - Coolant Temp. Sensor
1 wk ago - Opti spark Wiring harness ( Pigtail)

Now I'm lost....I'm to the point I either wanna sell it or its going to the shop and let them fix it......anyone wanna buy it.....???? 186K miles on a 1995 9c1 lol
 

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With no codes and the way you say the car dies, I'd suggest a bottle of gas line anti-freeze incase you have water in the gas. Pretty common problem up here in the winter to get condensation in the tank. Also have you bypassed the heater hose to the throttle body, if so "carburetor icing" will occur while driving causing the same problem you described.
Good luck.
 
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