hi guys, my 2004 manual spider won't rev clean when rolling. i can sit in the drive way and it revs free and clean but when i am driving it feels like it doesn't have much power and when i put it in nutral and still rolling and try to rev it the car is very slow to rev and misses and pops. i put it in gear and it drives smooth but with little power. i come to a stop and it revs fine. it initally felt like a blocked exhaust so i pulled out the front and back o2 sensors and put my camera down and had a look at the cats and they are fine. and exhaust gas flows from all the tail pipes any ideas i am pulling my hair out.... i have cleaned the air flow meters with no change, i have disconnected the air flow meters and no change i don't have any lights on the dash (cel lights or anything) i don't have any codes in the computer please help
Maybe there are codes but the CEL bulbs or slowdown lights are out? Get an OBD2 code reader to scan it. Basic stuff will show up even without the SD2 or Leonardo machine. Like O2 sensors, cat ecus if present, other sensors.
Wow! That's a strange one. I don't really have any ideas but, like you, I would focus on the air intake system. Seems like the logical place to start. I would try disconnecting the outside air intake and have the engine draw only the still air from the engine compartment. Maybe there is some kind of weird air turbulence due to a leaking manifold gasket? If that doesn't affect the problem, I'd put the car up on a lift and run it in gear. If the problem remains, it would seem to point to some sort of ECU interference from the rear wheel sensors. If not, you might try spinning the front wheels by hand, if that's possible. I don't know what else would be rotating while the car is coasting in neutral. Really strange you have no codes with so much misbehavior.
When I put the computer on the car and drive the air flow values for the 2 sensors give different readings when reving the engine when moving... One will go as high as 100 and the other stays about 60 then the other will come down to the same. At ideal they sit on 6 together. It seams to only happen at low rpm when you get higher in the rpm it seams ok just doesn't have any power
disconnect the gas padal connector to the fly by wire. spray with wd40, reconnect. try it. mine works that way. its the connector went bad.
I am going to have the fuel pressure check tomorrow as I don't have a tester... Is there any way to check the air flow meters are working right?
I am going to have the fuel pressure check tomorrow as I don't have a tester... Is there any way to check the air flow meters are working right?
Yeah, I removed the foot cover and disconnected the plug and spayed wd40 on the connector (both sides of the plug) and it's still the same
So I have the fuel pressure checked today and they both sit on 50-55 and stay even when driving... Also tried another set of air flow metres and they were worse than mine.. Has anyone had trouble with the intake variable runners ?
I'm no pro. What an odd problem. I think you need to determine if the problem is computer related and actually impacted by the wheels in motion, or due to maybe vibration. Take the car to a stretch of road on down hill. Stop and test the rev as long as good. Let the car idle and roll without using the engine. When up to speed try to rev it. When at speed take out of gear and shut engine. Restart while rolling does it rev normally? Do u have an obd reader that can give dynamic data from sensors. If not there are many available, some good ones for the smart phone. I would compare parameters at rest and in motion. Sent from my iPhone using Tapatalk
To me the key to this puzzle is the difference in the engine behavior when the car is rolling and when it is standing still. The question I would ask is how does the car know it's rolling. I can think of only two things - air flow into side intakes and the wheels rotating. As I said before, the air intakes can be disconnected and blocked from the outside so the car won't know it's rolling just from the outside air flow. It seems like a fairly simple test. If that has no effect, I would consider focusing on the wheel speed sensors.
i forgot one more thing: the TCU connectors, if they are loose, it can cause exactly your problem. mine did.
Good points. That's why it would be good to know if it is a data/computer problem with their interpretation of movement say from a speed sensor or a mechanical issue perhaps related to vibration from using engine to get to speed. What happens if the car is allowed to roll say down a hill in neutral while idling, how will it rev then? Sent from my iPhone using Tapatalk
The fuel pressure is good and I'm assuming that you've already checked for air leaks, bad intake gaskets ecetera... I'm leaning on either bad CKS or CPS. I have to replace both CKS on my 360 F1 to eliminate sporadic misfiring last year. I got CEL for misfires but no codes for a bad CKS. It's puzzling not to get any codes from the ECUs. You can throw expensive parts at it, but it's not the way to solve the problem. I would start collecting live sensor data by connecting a USB voltage data logger on each bank's sensor, download the data to your PC and start looking for anomalies on the waveform. It's very time-consuming, and you do need to understand what you're looking at in order to solve the problem. One advantage that you have is the symptom is repeatable.
thanks for all the help guys, the other thing that is happening is the exhaust sounds a lot differnt that it used too, i do have the valves disconnected and the lines plugged but it does not sound the same. i drove it tonight and the car runs really smoth if you don't put your foot down hard (so normal driving). if you put it in say third gear and try to punch it hard its really slow to rev until about 3500rpm then it feels a lot better still down on power but doesn't labour to rev, i check to ensure the variable inlet runner valve was holding acme and the butterflies are moving both sides but i don't know if the vacuum solenoid is letting the vacuum through at the right time or at all. i have read all the values on my hand held tool (it brings up both banks) and all the reading look good short fuel trims between +3 and -4 and the long term trims ar currently at -1.5 the timing seams to moving right and maxes out at about 31 the tps has a smooth curve the MAF sensors are reading good values (the same as i rev it) and the o2 sensors seam to be reading ok (secondary ones sit at 128 and go from - to + could be a glitch with my code reader) i checked the cat temps at both o2 sensors and the are the same temp from left bank to right bank i even tested the muffed and it reads consisted temps (hotter to the centre) I have also replaced the inlet gasket about 6 months ago and its been running fine so the issue of loss of power from 1000rpm to 3500rpm remains (but drives fine) i have only been doing 20-30min drives should i go on a longer drive to see if i can get the engine light to come on thanks for any ideas guys and gals
I'm no pro. So it doesn't appear have to be rolling, sounds like lower RPM when under load. Correct? I'm sure you already checked the air intake filters. I would re-torque the intake manifold for starters. Next pull injectors and have them professionally cleaned. replace coils. (And plugs) There are threads on this site that document identical Bosch coils for much less. Sent from my iPhone using Tapatalk
So I am takeoff the cars to put it on a dyno tomorrow ... I checked the exhaust temps before and after the cats and they are the same from the left to right side. Also checked the inlet manifold gasket that was only done about 6 months ago and it's all tight I also checked the variable intake runner arms under the manifold to ensure they are all connected and operate smooth and also checked the actuator and it works when I suck on the vac line I don't know yet is the solenoide that controls the vac to actuator is operating right I will hopefully be able to check it on the dyno.. Does anyone know if there is any issues with putting it in the dyno or do I just turn the asr off and I am good to go? I will keep you posted on how I go
Your car is running on one engine bank. Man a Prius could dust you off the line (smile). All kidding aside, computer related take it in to repair shop.
