High rev, no acceleration
#1
10-28-2014, 07:33 PM
High rev, no acceleration
Alright long story. I had two previous post tied in to this same scenario so i figured id start a fresh one so this makes more sense. Please dont hate me. About two weeks ago i think i had some bad gas in the car, car ran fine in the morning and afternoon, after fill up it went nuts. It had the heavy sputtering at idle and weak acceleration. I ended up draining the gas and changing the fuel filter. Nothing has changed, it still vibrates at idle and when slowing down under 10mph it shakes terribly. I cut the CAT off and had a fuel system cleaning this weekend and nothing changed again. I put in a new MAF and intake elbow to be on the safe side, still no changes. Yesterday I changed the fuel injectors and put in (ford denso 24#), cleaned the TB, the TPS and the IAC. Now the car does not idle lower than 1200 rpms and it does not accelerate past 10mph. It sounds like its miss firing and running rich. Before i end up throwing money away at a shop i would like your opinions and what you think i could do. I am super stressed with this. Thanks
#3
10-29-2014, 07:15 PM
It sounds like you now have a vacuum leak on top of your other issue. I doubt this was ever a "bad gas" issue. More likely just a coincident. There is no way anyone can tell you what is wrong with your car. You have a driveablilty issue with no check engine light. These are the ones that tend to go to the best mechanics and they have the equipment to test just about everything. All you are going to get on this or any other web site is "That happened to me and it was XYZ" If you start counting up the wires, connectors, control modules, grounds there are 100's of things that can cause this type of issue.
Step one is to look at the sparks electrical pattern on a auto oscilloscope. The pattern will show very quickly if the "miss" is from a failed ignition fire or from a lean or rich condition. That will answer the first question, Is the a fuel issue or a spark issue. You can even make out odd ball things like water (or coolant) in the cylinder.
Step one is to look at the sparks electrical pattern on a auto oscilloscope. The pattern will show very quickly if the "miss" is from a failed ignition fire or from a lean or rich condition. That will answer the first question, Is the a fuel issue or a spark issue. You can even make out odd ball things like water (or coolant) in the cylinder.
#4
10-30-2014, 05:38 AM
The opti is old. I did pull it before and clean it up. It may be original.
But with this scenario
I ended up replacing the IAC again and tightened all parts on TB. I still have the SES light on. I noticed that it idles around 1100 RPMS which is a little less than yesterday. The car also jumps a bit when shifting into gears like the gas pedal is stuck.
I also rented another fuel pressure tester today and my fuel pressure is around 30 psi when i prime the key and the pressure drops immediately. The FPR is new and the injectors were just put in. I am assuming its the fuel pump. it still smells rich and idles high, would lack of fuel cause that to happen? I'm installing a new fuel pump asap.
But with this scenario
I ended up replacing the IAC again and tightened all parts on TB. I still have the SES light on. I noticed that it idles around 1100 RPMS which is a little less than yesterday. The car also jumps a bit when shifting into gears like the gas pedal is stuck.
I also rented another fuel pressure tester today and my fuel pressure is around 30 psi when i prime the key and the pressure drops immediately. The FPR is new and the injectors were just put in. I am assuming its the fuel pump. it still smells rich and idles high, would lack of fuel cause that to happen? I'm installing a new fuel pump asap.
#7
11-02-2014, 08:33 AM
Ah good deal i will give this a shot again this evening, I tried it aboiut a week ago and it revved really high when i started the car while foot was on accelerator, I think i may have pressed it to far down.
Prior to reading this i reset the pcm and took the car out last night. I replaced the fuel pump and changed the tps sensor out. The SES light stayed off temporarily. so when i took the car out for a ride last night, it started off fine and drove fine. After it heated up all the problems started again, the heavy idle and very weak acceleration accompanied by a fluttering sound. I also noticed the interior lights flickering as well and the SES light going on and off. I attempted to go to oriellys to get ahold of the oBD1 scanner but i couldnt get past 20 mph. I seen this light flickering when the problems first started but it was pretty intense last night. I had the icm checked out and they said that was fine, i am going to pick up some heat sink grease from radio shack and apply that to the coil again. I noticed the copper braid wire that runs from the icm is loose, would that cause any issue if that wire made contact with any metal surfaces? Now since i did the fuel pump i am assuming this is straight electrical now, if this doesnt work i may have to lean towards the opti replacement. I went under the car last night as well and checked all the spark plugs i could reach, none of them looked bad.
Prior to reading this i reset the pcm and took the car out last night. I replaced the fuel pump and changed the tps sensor out. The SES light stayed off temporarily. so when i took the car out for a ride last night, it started off fine and drove fine. After it heated up all the problems started again, the heavy idle and very weak acceleration accompanied by a fluttering sound. I also noticed the interior lights flickering as well and the SES light going on and off. I attempted to go to oriellys to get ahold of the oBD1 scanner but i couldnt get past 20 mph. I seen this light flickering when the problems first started but it was pretty intense last night. I had the icm checked out and they said that was fine, i am going to pick up some heat sink grease from radio shack and apply that to the coil again. I noticed the copper braid wire that runs from the icm is loose, would that cause any issue if that wire made contact with any metal surfaces? Now since i did the fuel pump i am assuming this is straight electrical now, if this doesnt work i may have to lean towards the opti replacement. I went under the car last night as well and checked all the spark plugs i could reach, none of them looked bad.
Last edited by rs657f; 11-02-2014 at 09:02 AM.
#8
11-02-2014, 10:34 AM
1) Fuel injected cares should be started with the foot off the gas pedal, otherwise the PCM gets confusing signals.
2) The fuel pressure test you did indicates the fuel pressure is too low.
3) Flashing SES lamp indicates damaging misfire.
4) Raw fuel smell in the exhaust is the result of the misfire as the misfiring cylinder is dumping unburned fuel out the exhaust valve.
5) Just an observation, being that the engine starts to run poorly when it is fully warmed up is an indication that problem may be caused by a sensor. Cold engines run in open loop and many sensor inputs are ignored.
6) Braided wires are "usually" ground connections and need to be tight at both ends in order to avoid weird problems. If they are not ground straps they still need to be tight and should not touch ground.
7) Some of the parts you replaced need to be adjusted in order to work properly, and that requires test equipment.
7) My advice: You need to get an OBD1 scanner with an OBD2 adapter cable, or a scanner that can work with both OBD1 and OBD2, the latter is easier to find. Also, invest in a real Factory Service Manual.
It is very difficult to fix these cars without the proper test equipment, and by now you should realize that just throwing parts at then on a SWAG is just wasting time and money.
2) The fuel pressure test you did indicates the fuel pressure is too low.
3) Flashing SES lamp indicates damaging misfire.
4) Raw fuel smell in the exhaust is the result of the misfire as the misfiring cylinder is dumping unburned fuel out the exhaust valve.
5) Just an observation, being that the engine starts to run poorly when it is fully warmed up is an indication that problem may be caused by a sensor. Cold engines run in open loop and many sensor inputs are ignored.
6) Braided wires are "usually" ground connections and need to be tight at both ends in order to avoid weird problems. If they are not ground straps they still need to be tight and should not touch ground.
7) Some of the parts you replaced need to be adjusted in order to work properly, and that requires test equipment.
7) My advice: You need to get an OBD1 scanner with an OBD2 adapter cable, or a scanner that can work with both OBD1 and OBD2, the latter is easier to find. Also, invest in a real Factory Service Manual.
It is very difficult to fix these cars without the proper test equipment, and by now you should realize that just throwing parts at then on a SWAG is just wasting time and money.
Last edited by z28pete; 11-02-2014 at 10:39 AM.
#9
11-02-2014, 05:17 PM
1) i never have my foot on the pedal when starting
2) yes the fuel pressure was low new pump installed and it is at 40 psi
3) it doesnt flash, it has its moments, sometimes stays on for a few seconds and disappears for hours or days. (is back to back flashing what you are talking about)
4) yes it is running rich, doesnt seem to be as bad as before but that was in issue way before all this started happening.
5) I know its for sure electrical/sensor related. thats why i was mentioning that i see the dash lights flicker ect ect...
6) The copperish braided wire is the one that is bolted to the icm, it is a ground wire and is grounded to the frame. I am curious wire touches any thing would it cause some kind of reaction??
7) I tried to adjust the IAC using the steps from shbox, it doesnt seem to have to have worked. Car still idles at 1000 rpms. 95 z28 are supposed to be around 800 rpms from what i read?
8) the obd1 one is about to be ordered now. suggestions on where to get a decent name brand for a good price would be helpful, that why i reach out for help
I reapplied some more thermal grease to the back of the icm since all the grease i just put on dried out...what would symptoms of bad icm or opti cause? It seems to be one of those two parts.
Believe me i dont want play parts roulette, this is very frustrating and the shops in my area arent very comfortable working on this kind of engine. I also have the Hanes manual is garbage. what others manuals do you suggest? Not trying to be a **** here, just bare with me
2) yes the fuel pressure was low new pump installed and it is at 40 psi
3) it doesnt flash, it has its moments, sometimes stays on for a few seconds and disappears for hours or days. (is back to back flashing what you are talking about)
4) yes it is running rich, doesnt seem to be as bad as before but that was in issue way before all this started happening.
5) I know its for sure electrical/sensor related. thats why i was mentioning that i see the dash lights flicker ect ect...
6) The copperish braided wire is the one that is bolted to the icm, it is a ground wire and is grounded to the frame. I am curious wire touches any thing would it cause some kind of reaction??
7) I tried to adjust the IAC using the steps from shbox, it doesnt seem to have to have worked. Car still idles at 1000 rpms. 95 z28 are supposed to be around 800 rpms from what i read?
8) the obd1 one is about to be ordered now. suggestions on where to get a decent name brand for a good price would be helpful, that why i reach out for help
I reapplied some more thermal grease to the back of the icm since all the grease i just put on dried out...what would symptoms of bad icm or opti cause? It seems to be one of those two parts.
Believe me i dont want play parts roulette, this is very frustrating and the shops in my area arent very comfortable working on this kind of engine. I also have the Hanes manual is garbage. what others manuals do you suggest? Not trying to be a **** here, just bare with me
Last edited by rs657f; 11-02-2014 at 05:22 PM.
#10
11-02-2014, 08:26 PM
Join Date: Mar 2009
Location: Tokeland, Washington
Posts: 21,637
dang i should have told you to set your minim idle, if you have a vacumm leak i dont think anything is going to help. if your thottle body settings has been messed with they may need reset. do you have a stock tb