trooper1100 surge

[lowgear]

has anyone heard of a engine surge between 2000 and 3000rpm any gear under light or constant throttle. i have checked every thing that can be checked. i have even replaced some of the sensors trying too find the problem. HELP jim

[ricksrb]

has anyone heard of a engine surge between 2000 and 3000rpm any gear under light or constant throttle. i have checked every thing that can be checked. i have even replaced some of the sensors trying too find the problem. HELP jim

You say you checked everything. Does that include fuel regulater and fuel pump? when you say surge does it loose power and then surge or keep same rpm and surge to more rpm?

[Guest Lenny]

has anyone heard of a engine surge between 2000 and 3000rpm any gear under light or constant throttle. i have checked every thing that can be checked. i have even replaced some of the sensors trying too find the problem. HELP jim

There are a number of things that could cause that. I would think that if it doesn't do it above 3000 rpms, it should be getting fuel ok. But check that just the same. Try disconnecting the IAC, idle air control on the throttle body. It can run fine without it but, it may not idle correctly and you may have to adjust the throttle butterfly stop screw on the throttle body to get it to idle. Check all your connections by unpluging them and reinserting them. A loose of poor connecton could be intermittenly breaking the circuit at a certain rpms viabration. Try switching your air fuel sensors that are on the exhaust. One is before the converter and the other after. You will have to cut and splice the wires because the plugs are different. This sensor tells the computer if it needs more or less fuel buy looking at the first sensor to see if there is too much fuel left in the exhause gases or too much oxygen. The computer then adjust for the condition. If the sensor was bad, it could cause the computer to get confused. I'm not sure how it woulld act if the second sensor is bad. That sensor is for EPA compliance. Either way if one is bad and you switch them it shoud run different telling you that one of the sensors is bad. I think Auto zone can check them for you if you bring them in or google it for how to check them yourself. Make sure your spark plug wires are not touching the head. If they were bad or in poor condition, they can cause misfires but not surging so quick. If your throttle position sensor on the throttle body had a bad spot in it, it could give the computer bad information at that point. For example, the computer might get the wrong voltage from the sensor making think you let up on the throttle when you really didn't or are accelerating when your not. When it is between surges is it blubbering or acting like its out of fuel momentarily. Obviously when it's surging, it's not low on fuel at that moment. If it's blubbering in between surges, it's probably getting too much fuel then cleans itself out. If it's just cutting out then it's probably not getting enough fuel momentarily. you could unplug the knock sensor which is just behind the starter on the side of the block. I think it will run with this unpluged. Keep in mind that most all the sensors are to give the computer signals that indicate rather it needs more or less fuel or more or less timing. It may not be anything of these things but if you methodically go thru stuff and check where you can at least you can eliminate potentials. Without a computer code signal reader, you can only keep hunting. I'm sure some of the other forum guys will have some good ideas too.

Lenny

[MauyThai1]

There are a number of things that could cause that. I would think that if it doesn't do it above 3000 rpms, it should be getting fuel ok. But check that just the same. Try disconnecting the IAC, idle air control on the throttle body. It can run fine without it but, it may not idle correctly and you may have to adjust the throttle butterfly stop screw on the throttle body to get it to idle. Check all your connections by unpluging them and reinserting them. A loose of poor connecton could be intermittenly breaking the circuit at a certain rpms viabration. Try switching your air fuel sensors that are on the exhaust. One is before the converter and the other after. You will have to cut and splice the wires because the plugs are different. This sensor tells the computer if it needs more or less fuel buy looking at the first sensor to see if there is too much fuel left in the exhause gases or too much oxygen. The computer then adjust for the condition. If the sensor was bad, it could cause the computer to get confused. I'm not sure how it woulld act if the second sensor is bad. That sensor is for EPA compliance. Either way if one is bad and you switch them it shoud run different telling you that one of the sensors is bad. I think Auto zone can check them for you if you bring them in or google it for how to check them yourself. Make sure your spark plug wires are not touching the head. If they were bad or in poor condition, they can cause misfires but not surging so quick. If your throttle position sensor on the throttle body had a bad spot in it, it could give the computer bad information at that point. For example, the computer might get the wrong voltage from the sensor making think you let up on the throttle when you really didn't or are accelerating when your not. When it is between surges is it blubbering or acting like its out of fuel momentarily. Obviously when it's surging, it's not low on fuel at that moment. If it's blubbering in between surges, it's probably getting too much fuel then cleans itself out. If it's just cutting out then it's probably not getting enough fuel momentarily. you could unplug the knock sensor which is just behind the starter on the side of the block. I think it will run with this unpluged. Keep in mind that most all the sensors are to give the computer signals that indicate rather it needs more or less fuel or more or less timing. It may not be anything of these things but if you methodically go thru stuff and check where you can at least you can eliminate potentials. Without a computer code signal reader, you can only keep hunting. I'm sure some of the other forum guys will have some good ideas too.

Lenny

I had the same problem so I eliminated the "cat converter" and both oxigen sensors, seems to have fixed it. Keep in mind I also have a Turbo.

[lowgear]

thanks for all the replies i disconnected the ox sensors and removed the cat long ago. the idle air control has also been disconnected. i have had all the elec. con. apart and cleaned. the tps has been replaced along with the map, speed, and coolant sensors, also the fuel pump. i moved the fuel filter to just past the pump, and the fuel line from the tank is now 5/8 id line. the map sensor was the last to be replaced and the surge got worce go figure. the rpm's go up then back no blubber or any other condition happens when it surges. to me it seems like timing jumping because it is so quick. i disconected the idle sensor long ago because with it con. the idle would jump up to 3000to5000 rpm. i could not find that problem either. the fuel pressure does not change when it surges. do you have any more suggestions

[ricksrb]

thanks for all the replies i disconnected the ox sensors and removed the cat long ago. the idle air control has also been disconnected. i have had all the elec. con. apart and cleaned. the tps has been replaced along with the map, speed, and coolant sensors, also the fuel pump. i moved the fuel filter to just past the pump, and the fuel line from the tank is now 5/8 id line. the map sensor was the last to be replaced and the surge got worce go figure. the rpm's go up then back no blubber or any other condition happens when it surges. to me it seems like timing jumping because it is so quick. i disconected the idle sensor long ago because with it con. the idle would jump up to 3000to5000 rpm. i could not find that problem either. the fuel pressure does not change when it surges. do you have any more suggestions

I am by far no expert and dont have much knowledge but could the ECU be confused because of all the sensors being disconnected ?

[Guest Lenny]

My guess is that the oxygen sensor needs to be hooked up. The throttle position sensor doesn't matter nor the IAC.

Lenny

[lowgear]

My guess is that the oxygen sensor needs to be hooked up. The throttle position sensor doesn't matter nor the IAC.

Lenny

I don't think it matters if it is hooked up, it's been disconnected for 2 years. I would have to buy a new one and weld in a new mount and replace the missing wires.

[lowgear]

I am by far no expert and dont have much knowledge but could the ECU be confused because of all the sensors being disconnected ?

the only sensor disconnected is the IAC, but I'am beginning to think the ECU is my problem.

[Kinarfi]

My guess is that the oxygen sensor needs to be hooked up. The throttle position sensor doesn't matter nor the IAC.

Lenny

The throttle position sensor doesn't matter ??? Isn't the TPS used by the computer to know how much gas to inject?? plus the MAP / IAT???

Kinarfi

[Guest Lenny]

The throttle position sensor doesn't matter ??? Isn't the TPS used by the computer to know how much gas to inject?? plus the MAP / IAT???

Kinarfi

Your are right Kinarfi. However the TPS is used by the computer to know when to add extra fuel on acceleration. The amount depends on how rapidly you push the gas pedal down. I think it may also cut the fuel when you let up on the throttle quickly. The reason I said it didn't matter is that when just crusing along, it does nothing so by disconnecting it at least you take it out of the equation justin case it's defective and sending signals it shouldn't be sending to the computer. As for the oxygen sensor, It will actually work either way, connected or not but it could make a differance. The computer has a table it looks at to decide how much fuel the engine should need based on engine temperature, manifold vacume/pressure, rpms and load on the engine which it can see from the amount of fuel it's giving the engine compaired to the rpms. There are set values in the tables for various conditions. There are tables for injector pulse width and and timing along with various tables for special conditions like when you start the engine if it's lclod or warm. There are tables for telling the computer how much more or less to add fuel if your accelerating (throttle down) for example. These are the tables I or my dyno guy will change when tuning the engine. If your racing a vehicle, then you tune it for those specific operating conditions but that tune wouldn't work for your family car very well. A race car doesn't need an oxygen sensor because the tune is alreaqdy perfect for it's use, no adjustments by the computer are needed. However in a family car for example you may drive from the freezing mountain temperatures to 80 degree weather an hour later or towing one day and not the next As a result, the tables are no longer real reliable so the compputer looks at the oxygen sensor to see if it's getting the right fuel/oxygen ratios. With out the oxygen sensor, you may run ok in very normal conservative conditions which represent the condition the tables were tuned for but if your towing or hot rodding then the oxygen sensor can play a big roll by helping the computer to know when things arn't quite right soit can adjust things. It's also asssisting in EPA compliance by making sure the engine is getting enough oxygen to burn the fuel completely.

Sorry for the long explainations on things but I just don't llike to just give yes or no answers on techneticasl issues. I like to explain them not only to help others understand the why for things but it also shows how my thinking is going so if I'm wrong on something, someone out there will correct me and I too can learn more.

Lenny

[Kinarfi]

The throttle position sensor doesn't matter ??? Isn't the TPS used by the computer to know how much gas to inject?? plus the MAP / IAT???

Kinarfi

Sorry for the long explainations on things but I just don't llike to just give yes or no answers on techneticasl issues. I like to explain them not only to help others understand the why for things but it also shows how my thinking is going so if I'm wrong on something, someone out there will correct me and I too can learn more.

Lenny

No apologies needed, thanks for sharing what you've learned from changing you system, that was an excellent answer.

Kinarfi

[lowgear]

i have somthing too add. i know have stumbling when i shift and reapply throttle, it does this only when i am easy on the throttle and i don't run up the rpm. Lenny, i tried hooking up a knew o-sensor, it totaly screwed up the way it ran. it had all kinds of problems, it ran lean, stumbled, would start but idle was erratic, sometimes while accelerating it would flaten out then go again. i tried too find someone who had an ecm reader, but no luck. living in Quartzsite can be a problem i am too far away from everything. i was thinking before that my ecm was bad but i realy don't want too buy one yet they are just too much money, just to find out that is not the problem.

[lowgear]

I tried a computer off another t2 it did the same thing. I know this is a very wierd problem but if anybody gets another idea please let me know.

[Kinarfi]

One thing I didn't like about our injector system, is that if anything got past the pressure regulator, it was stuck in the fuel rail forever. What I did was drill a small hole, very small, in the end and put some brazing on it so I could solder a small barbed brass fitting on it, solder won't stick to stainless, and then drain the flow from there back to the tank, that way if it had filled with water over time or something else, It now has a way out.

Kinarfi

[Guest Lenny]

I think I still have my stock injectors around. If you want to try changing out the injectors, I could send these to you to try. If they don't do anything, send them back otherwise if they help and you want to keep them send me $25 for each injector you need. They are real easy to change out, takes only about 15 to 20 minutes. You can alsosort of take a look at how your injectors are doing. If you remove the fuel rail and leave the injectors clipped into it, you can crank the engine and they should sequentually fire a mist spray. If you do this, BE CAREFUL, and have a fire extingusher handy and prefererable do it outside. You don't want a fire so be quick about the check. This can give you a hint of any of the injectors that don't spray right (plugged). You only have to turn the engine over once or twice. Len me know. You might want to also add an extra fuel pressure gauge where the fuel line goes into the injector rail. Gauges are cheap. Have someone monitor this as you drive it to see if the pressure stays constant at the rail. It should be somewheres between 45 and 55 psi. but not fluctuate. It will increase some if you have an air line runnning from the intake plentum to the regulator, when you push the throttle down but should be rock steady when crusing..

Lenny

[lowgear]

I will give everything a try thanks.

[lowgear]

I checked everything out no luck. I disconnected the speed sensor for something different. The surge lessened significantly and changed slightly in the rpm band, instead of 2000 to 3000rpm it went to 2100 to 2700rpm. The surge when shifting stayed the same. Does the crank sensor only send one type of signal to the ecm or is it a multiple type sensor that sends more than one impulse. The flywheel has more than one knob that could be sending more than one signal, with more than 2 wires on the sensor I was thinking that it might be doing just that. It has always seemed to me that the surge is timing related because of the consitantcy of it, always between 2000 and 3000 rpm and the rappidy of it, like flicking a switch and yes I have already changed out the speed sensor but not the crank sensor.

[Guest Lenny]

I don't think that the crank sensor does more then one thing but I'm not for sure on that. I do have a crank sensor that I no longer use and could send it to you if you want to try it. Let me know. I have gone to an Edis spark and use a 32-1 timing wheel on the fornt of the engine and that gives me my crank timing. Try typing "what causes engine surging" into Google. Lots of thgings to read.

Lenny

[missedapeach]

Well I'm no mechanic but just thought I'd share because for months now I've been trying to figure out why my 2018 T2 1100cc was surging like air was getting in somewhere.. and it was!!  On the back side of the intake below the air filter (its metal) and again sorry for the ignorance, but their are two vacuum ports, inside has a hose attached to it and the one closer to me had nothing on it and when I put my finger over it and had my husband start it, the surge was GONE! maybe I'm getting excited over something simple but we never noticed it before.  Hope it helps for someone with the same problem.