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Truck bogs and buks, and ABS and BRAKE lights come on!!!
so... all of a sudden everytime I take off (or speed up from slow), the truck bogs down and bucks like it wants to die (but it hasnt died yet), and both the ABS and BRAKE warning lights come on. If i throttle through it, the lights go away and shell run fine till i have to speed up from stopping or slowing down.
HELP!!! |
Is the CEL on as well? Does the speedo jump around at all during all of this?
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CEL does not come on at all when it happens. I havnt noticed wheather the speedo jumps, but the RPMs jump around a bit.
EDIT: Just went out and read the codes; no MIL but she did have a P1406 which I cleared. I have a scantool, so Im thinking I should go for a drive and see if my passenger can spot any specific sensors that are going nutz! Any Ideas? |
P1406 refers to a problem with the EGR pintle position. A malfunctioning EGR could cause the symptoms you describe. I think the ABS and Brake lights indicate a different problem altogether. Try this:
If your SES or CES light came on and you pull a P1406 code from your PCM, try this before you pay a shop to fix it: Remove your EGR valve and soak it in about an inch of good carbon cleaner. Dont submerge the whole thing, just the bottom part where the valve seats. Leave it overnight and clean it really good the next day with a pick and a brush. (a small screwdriver and an old toothbrush work just fine.) Push open the valve and carfully clean any carbon built up around the valve and seat. The valve should move freely and NOT stick in the closed position. When the valve is dry, reinstall it and clear the codes. |
If the truck is laying down hard it'll set the ABS light off. (quick deccelaration with no brake switch application). I had a CKP sensor that would malfunction only under hard throttle, when the truck died the ABS light would come on. And yeah, a malfunctioning EGR valve will do that too.
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P1406 - EGR Valve Pintle Position Circuit
I would start by removing the EGR valve and giving it a thorough cleaning. While the valve is off, make any attempt you can to clean the supply line from the exhaust manifold and the feed line to the intake. This code can be caused by a restricted or blocked feed or supply line. |
ill go pull the egr and swap it with my swapper egr on the shelf. p1406 is usually always in the truck. i clean the egr every few months, it was cleaned a moth ago, but ill give it another shot!
any other sugestions in the meantime? what would happen if something was binding the tranny? could that cause anything close to this? let me know, i pretty much need to squash this bug today!!! help! |
Originally Posted by Ugly_Monkey
(Post 284982)
ill go pull the egr and swap it with my swapper egr on the shelf. p1406 is usually always in the truck. i clean the egr every few months, it was cleaned a moth ago, but ill give it another shot!
any other sugestions in the meantime? what would happen if something was binding the tranny? could that cause anything close to this? let me know, i pretty much need to squash this bug today!!! help! P1406 - EGR Valve Pintle Position Circuit Schematic http://i11.photobucket.com/albums/a1..._P1406_sch.gif Circuit Description The Vehicle Control Module (VCM) constantly monitors the linear Exhaust Gas Recirculation (EGR) valve pintle position sensor to ensure that the valve is responding properly to commands from the VCM. The DTC P1406 is a type A DTC. Conditions For Setting The DTC The Following Conditions will set the DTC: ^ EGR pintle position signal indicates a voltage out of the normal range of the pintle position sensor, or a signal that is 10% greater or less than the VCM commanded position. ^ Ignition voltage greater than 9 volts. Action Taken When DTC Sets If a current DTC P1406 sets during 2 consecutive test cycles, the VCM turns on the Malfunction Indicator Lamp (MIL). Conditions For Clearing The MIL/DTC The VCM turns the MIL off after 3 consecutive driving trips without a fault condition present. A history DTC will clear it no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used. Diagnostic Aids A poor connection or rubbed-through wire insulation may cause an intermittent. Check for the following conditions: ^ Poor connection or damaged harness - Inspect VCM harness connectors for backed out terminals BL18, GR27, GR19, or RE1O for the following items: ^ Improper mating. ^ Broken locks. ^ Improperly formed or damaged terminals. ^ Poor terminal to wire connection. ^ Damaged harness. Intermittent test - If connections and harness check OK, monitor a digital voltmeter connected between affected terminals and ground while moving related connectors and wiring harness. If the failure is induced, the voltage reading will change. Diagnostic Charts http://i11.photobucket.com/albums/a1...6_diag1of4.gifhttp://i11.photobucket.com/albums/a1...6_diag2of4.gifhttp://i11.photobucket.com/albums/a1...6_diag3of4.gifhttp://i11.photobucket.com/albums/a1...6_diag4of4.gif Test Description The numbers below refer to the step umbers on the diagnostic table. 2. Checks for an EGR valve sticking partially open or an incorrect pintle position sensor feedback signal. 3. Ensures that the VCM is capable of controlling EGR pintle position and is reading the pintle position feedback signal properly. 4. Checks the EGR valve driver in the VCM and the EGR LOW signal circuit. 5. The checks for an incorrect EGR pintle position sensor input signal. This test verifies a 5 volt reference at the EGR valve. |
Im not ignoring the advice given, i am simply trying to consume all usefull information as i can WHILE i deduce this problem. like i said; i have today to fix this so ANY oppinions about what MIGHT be going on are welcome! i am attempting to rule out the egr as we speak.
thank you. any ideas, help! EDIT: After furthore testing i dont think the p1406 has anything to do with whats going on. Im thinking ABS module, but hopeing maybe its a sticking drum or caliper. the enginge sounds like she is running fine, but the abs ligh goes on then the ebreak light then they both go off. i just took her for a spin and the only way i could get it to happen was gunning from a stop and turning sharp. but the traffic is not the same as yesterday. abs module? stickey drum/caliper? help? |
What kind of scan tool do you have? Will it pull ABS codes?
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I have an ELM327 based tool. I dont believe any of my current software will pull ABS mod code. but anyways...
I have changed my mind once again... after furthore testing this problem is definatly FUEL/Air system RELATED!!! I can rev the crap outa the engine in any gear while stopped and she runs fine. however under loaded throttle (trying to actually move the truck) she spits and stumbles and stalls ONLY at the low end! if i can throttle through the hicup then every thing is fine again untill i slow down to the low end. HELP! Im trying to do searching but i dont know. I cleared all the codes yesterday, so im going to go for another spin with the software running and see if i can see any abnormalitys in one of the sensore realtime. I apreciate all the help so far, and i engourgage anyones ideas about what this might be. maybe im an idiot and this is just another symptom of my cloged cat? maybe i should go beat it with a hammer, lol again, thanks, and HELP!!! |
OK, so... she is choking sputtering under darn near any load. i had my girl watch the numbers on the laptop as we drove and she said that the fuel trims were going to -99% when the truck would go nuts.
it was getting really bad (almost wouldnt go up hill at all with out hammering the throttle trough all the bucking) and my gas was at between 1/4-1/2 tank, so i went and got 20$ of gas and coincidence or not the symptoms seemed to lighten up. i already have a fuel filter that i just havnt replaced yet so im going to do that. this seems very fuel system related. the p1406 got thrown again so i did the relearn when i wiped it, but have not drove it again yet. help! and this may be wierd or unrelated but i feel like this last tank of gas lasted a long time. whether that be it LOOKed like it lasted a long time or whether it did. help! |
Go buy a fuel pressure gauge and check it. Sounds like the pump may be about to give up.
HELP! Im trying to do searching but i dont know. I cleared all the codes yesterday, so im going to go for another spin with the software running and see if i can see any abnormalitys in one of the sensore realtime. |
MIL is off, changed fuel filter to no avail. pump is not making any strange noises and sounds like its working fine. (Im not saying it is fine, just that it sounds fine.)
installing fuel pressure guage tomorrow. I don't know what to say about this problem, I'm at a loss! |
Had a problem like this once on my old truck. Come to find out it was a spark plug wire breaking down but only under high load (like just giving it enough gas to get up a not to steep hill). When I floored it, the problem went away. You could check the resistance in your plug wires without removing them. Doesn't take too long. Most manuals give a resistence range.
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Originally Posted by Gimpy Blazer
(Post 287087)
Had a problem like this once on my old truck. Come to find out it was a spark plug wire breaking down but only under high load (like just giving it enough gas to get up a not to steep hill). When I floored it, the problem went away. You could check the resistance in your plug wires without removing them. Doesn't take too long. Most manuals give a resistence range.
she runs and idles great, its just under uphill load or hard throttle. and it doesnt seem to happen till she at least a little warm. like shes fine up the first hill in the am (i think, this is largely based on a few assumtions) but after that i start having trouble. the bonus is i have to drive like a grandma, so im doing good on mpg lately, lol. can you explaine this testing without removing the wires? or point me to a resource possibly? |
I'd sure like to know how to check resistance in the wires without removing. I'm thinking it's not possible.
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Don't know about an 2001 but I have a Chilton book up to 1995 that gives this procedure. Remove the distributor cap and the wire at the spark plug. Measure resistance from electrode inside the cap to wire end at spark plug. Maximum value should be less than 30,000 ohms and preferably less than 25,000 ohms. Of course the resistance depends on wire length. They give the following values.
0 - 15 in. 3,000 - 10,000 ohms (didn't know you could have a wire 0 in long) 15 - 25 in. 4,000 - 15,000 ohms 25 - 35 in. 6,000 - 20,000 ohms Wire over 35 on. 6,000 - 25,000 ohms My 1994 factory Service Manual (Section 6D4 [Engine Ignition System] Spark Plug Wire Resistance Test) calls out the same values only with the wire disconnected at both ends. It also states that if the reading is above 30,000 ohms, or fluctuates between infinity and any value replace the wire regardless of length. Like I said, I'm not familiar with the models later than mine. If this doesn't work for you ignore it. It worked for me on both my 84 Jimmy 2.8L and 94 Blazer 4.3L Vortec. Just trying to help. Sounds exactly what hapened to me. Felt like the truck hit a brick wall when it missed. Can't believe nobody's heard of this. |
Ok soo...
Installed fuel pressure gauge. At idle pressure sits at 50psi. ignition on, engine off sits at 60psi. driving sits at ~47psi. depending on throttle, pressure may fluctuate ~3psi in snaps. ie ( throttle/let off ). so is this my fuel pump or my fuel pressure regulator? or do i have a poppet leaking pressure? |
I know you mentioned having a new fuel filter on hand, but have you installed it yet? Your key-on/engine-off pressure looks good, but it seems quite low when under load. This would point towards a supply issue which could be caused by a restricted fuel filter.
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I did the fuel filter the other day and it made no difference. (old one was visually clean aswell.)
my ignition on, engine off psi comes up as ~50psi sometimes ( ie: trucks just been shutoff ), but if i turn off the ignition then on again it jumps up to a stable 60psi. NOTE: this is all assuming that my electric pressure gauge is actually calibrated correctly(wich i assume it is). |
our s-10 did the same thing except the gauges would sometimes jump to 0 while driving. They said the brake and abs lights can be cause by burning the tires. something about the sensor cant keep up. As far as the bogging, for us it was the fuel pump.
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it has never dropped to zero {EDIT: i just noticed you were refering to the instrument cluster; those guages all work fine, never drop either}, and this keeps getting wierder to me because. if i say mash up a hill, ill be at 60psi by the time im halfway up but if i let off the pettal itll drop down to ~50psi. if i mash back on it, itll do it again. but on flat ground (hardly any load) no matter how hard i romp on it it just chills at ~50psi.
also the stumbles, rough running, yada yada dont seem to coralate to any fluctuations on the pressure guage. iE: when it stumbles it does so reguardless of whether the fuel pressure is 47psi or 60psi. So is there any specific tests i can do to tell if my pump is bad or if its a diffrent component? Ive heard of people pinching off the return line to see if a pump is the problem or the FPR, but our fuel lines are all metal so i dont see that working. |
could be the fuel pressure regulator
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Originally Posted by 1998ZR2
(Post 287945)
could be the fuel pressure regulator
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You could test the dead head pressure of the pump by removing the fuel filter and installing the gauge at that location. Energize the pump and see what the reading is.
You can run down the Fuel pressure test as defined in the Tech Article (DIY) section which should also leave you with an indication of what, if any, problems exist. |
Originally Posted by swartlkk
(Post 287982)
You could test the dead head pressure of the pump by removing the fuel filter and installing the gauge at that location. Energize the pump and see what the reading is.
Moved from wrong thread: Ok, soo... what makes the pump spool up when you turn the ignition to on? seems it doesnt do it every time. ALSO just wiped the codes again and had the good ol p1406 thats allways chillin and a new p0446! |
Yes, you connect your gauge to the line that comes from the pump.
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*Ding* *Ding* *Ding* Gimpy is the winner!!!
...turns out it was a bad wire!!! |
Originally Posted by Ugly_Monkey
(Post 301173)
*Ding* *Ding* *Ding* Gimpy is the winner!!!
...turns out it was a bad wire!!! I just thought I would post too. I had the 100% exact same scenario last week. I have a constant p1406 that seems to be unrelated but that I can't get to go away. At first I thought the bucking was a fuel issue since I had a cold start problem as well. A new pump fixed my cold start problem but the bucking and jerking with ABS and Brake light I thought had to be an electrical issue since lights were flashing randomly all over the dash when it happen. I had already put a new distributor, rotor, cap and plugs in it. Wires were the last thing ignition wise to try and sure enough I put a new set of wires on Saturday and the issue disappeared. It's weird we were dealing with the exact same issue at the same time. Too bad I didn't see this post earlier. :) Thumbs up for both of us!!! |
Ok, so...
Everything thus far seems to have just been a band-aid. This weekend she started sputtering way out of control, cant go more than 50 feet without choken out! I got an appointment at the closest dealership tommorow. 92$ for a diagnostic, I hope they can decide what the heck is wrong. It is proly the fuel pump or regulator, but IDK. All I know is I dont have time to troubleshoot on this one any more. I let you guys know what the doctor says! |
Hey peoples!
...So, long story short... The dealership had no idea what was wrong and wanted way to much money to 'try' things. I eventually decided to just get a new(used)ECU. Poped in the ECU and she's been runnin like a champ ever since, and the bonus is all my performance parts can actually enhance performance now! yay! It seems my old ECU was toast, and apparently all my sensors were going nutz because they did not have a steady refrence voltage. I just wanted to say thanks for everyones ideas! :) |
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