Engine Hesitates

Dave In Indy · 08-13-2009, 02:50 PM

My engine hesitates between 3500 and 4500 r.p.m. and starts rough. I have replaced the fuel filter, air filter, all ignition components, the ECU, the catalytic converter, and the O2 sensor. The only codes I get are 5 and 1 which means no code set. My guess is it's either the timing, a clogged injector, or a bad EGR valve. The car doesn't smoke or anything so I don't think it's a compression issues. It revs fine to 3,500 r.p.m. and quickly revs up after 4,500 r.p.m. and on. Everything inbetween that zone is a dead spot and it is kindy of jerky as it revs in that area. Anyone ever seen this.

Indysw20 · 08-13-2009, 03:40 PM

Have you done anything new to the car Service, Mods, Weather? When did you replace all the listed items? Im not sure about the EGR i had a avalon that had an egr problem that would jump from 2 to 3 rpm, i had a mazda and it wanted to stall out with an egr problem..DIrty throttle? just throw stuff out there.Im on ss of indy if you need help or what not

Dave In Indy · 08-14-2009, 08:22 AM

I replaced everything over the last two weeks. I have even swapped this engine out of one car into the other so I've eliminated anything to do with the fuel tanks computers and the like. I retimed it last night and it is still doing it. I cleaned the throttle and that didn't help. I'm going to pull the injectors this weekend and clean them. The EGR is so rusted up I'm afraid I'll have to break the hoses to get it off.

mr2tim · 08-14-2009, 02:48 PM

If you have swapped out the engine the TPS and the AFM meter were also replaced without change in conditions?

If so, perhaps you should run continuity checks on all 7 wires from the AFM connector back to the ECU in the trunk. Concentrate on Vb, Vc and Vs circuits.

Pm me for BGB pictures if needed.

Dave In Indy · 08-15-2009, 11:43 AM

Alright, I replace the AFM with a know good one, and it still did it. So I checked all the vacuum hoses and valves associatted with the emmisions system. Plus I changed all the filters in the emmisions system. Then I pulled all the injectors and cleaned them. They all looked good except the cold start was covered in oil and goop from the PCV hose being upstream from the injector. It still is sluggish and jerky through 3500 to 4500 r.p.m.s. I'm thinking maybe it has something to do with the TVIS system possibly. What does the TVIS do? It seems as if the car is just out of time within that R.P.M. range. I'm sure someone has had this problem.

Allmotor87mr2 · 08-15-2009, 01:07 PM

the tvis (Toyota Variable Induction Syatem) has 8 intake ports going in to the head it only uses 4 of them till a certen rpm than a vacuum actuator opens the butterfly valves than all 8 open. it could be that your butterflys are gumed up and geting stuck or something. the best way to clean it is to take off the manifold and clean it out with amsoil manifold cleaner or some kind of carb cleaner. blow dry and instll its something to try. make sure your vacuum actuator on the manifold is worken. let me know if that dosent work.

Jackstand Queen · 08-16-2009, 12:29 PM

I second Allmotor87's diagnosis about the faulty TVIS gadget.

Allmotor87mr2 · 08-17-2009, 10:18 AM

yea its probley that ive had that problem before. my vac hose was cracken and my manifold was dirty as .... if it dosent work ive got a few other things you can try.

Dave In Indy · 08-19-2009, 08:56 AM

I'm leaning towards a vacuum hose at this time, but I haven't pulled the intake yet. I'm planning to do it this weekend. The bog has gotten a little worse and is now 2500-4000 r.p.m. area. The car revs fine when it's not under load and even in first gear. As soon as I hit second is when the bog starts getting noticeable. Also it does not seem to bog for the first couple of minutes until it warms up. And the transmission does not want to go into first or reverse when it warms up. It is a manual and did not do that before the clutch was replaced. I don't know if they are related or not.
To recap what I know
It is not the EGR system
It is not the AFM
It is not the timing
It is not the injectors
It is not the PCV system
It is not the TPS

I'm pretty sure it's a dirty intake which I'm going to mess with Friday night.
I also bought new vacuum hoses to put on it.

Allmotor87mr2 · 08-19-2009, 05:12 PM

yea it should be that. the reason its prob worse when the engine is warm is the dirt and oil in the mani get gummy causeing the butterflys to stick. i hope cleaning it solves the problem good luck.

Dave In Indy · 08-20-2009, 08:46 AM

Well, I found a few other issues. I pulled the plugs and did a read. 3 were white and orange colored, and one was black and oily. These plugs are less then a month old. There is a lot of oil leaking from the valve cover into where the plugs are at. I think the plugs might be he wrong temp range, or the gap is wrong. So I'm going to try replacing them again.

Jackstand Queen · 08-20-2009, 10:04 AM

I'd put money on a broken ring, or leaky headgasket related to the odd spark plug.

It looks like it might have to go under the knife to me. Open her up, like a Can O' Beans.

dirocyn · 08-20-2009, 11:58 AM

Quote:

Originally Posted by Dave In Indy

Well, I found a few other issues. I pulled the plugs and did a read. 3 were white and orange colored, and one was black and oily. These plugs are less then a month old. There is a lot of oil leaking from the valve cover into where the plugs are at. I think the plugs might be he wrong temp range, or the gap is wrong. So I'm going to try replacing them again.

Test your compression wet and dry, so you can figure out if that oil is the ring or the valve guide. The orange glaze on your plugs is either from a fuel additive (octane booster) or from rust in your fuel system.

On this hesitation, my gut says it's something to do with TVIS. When TVIS engages, your engine goes from having 4 intake valves to 8, and that happens in that rpm range. If you had a vac leak when TVIS opens, your engine would stumble until the ECU can compensate and get the fuel/air mix right.

Dave In Indy · 08-20-2009, 02:08 PM

Found the majority of the problem, I had a plug with a cracked insulator, and they all look like they got hot. The engine compression was 120 in all cylinders which thrilled me. I went colder on the new plugs and platinum. I had NGK BCPR5ES11 in there now I have NGK BCPR6EGP plugs in there. With the plugs in it seems okay so far though I won't know until I drive home tonight. I'm thinking there may be some air in the cooling system because the engine feels very hot. I'm crossing my fingers it's good to go. Here's a pic of what I found on the one plug.

Jackstand Queen · 08-20-2009, 02:49 PM

120 PSI seems low to me.

I had a Jspec N.A. engine that had all cylinders in the 195 to 200 PSI range.

muffinman · 08-20-2009, 02:53 PM

Quote:

Originally Posted by Jackstand Queen

120 PSI seems low to me.

+1

Dave In Indy · 08-20-2009, 03:22 PM

Sorry I thought 120 was normal. I just read the book and it said 179 to 149. So that is not a good thing. It is a Harbor Freight gauge so I'm taking it with a grain of salt. There is a lot of air in the cooling system so I'm going to bleed it out before I leave today. I had no idea there was a bleeder, needless 3. I'm going to run another compression test tonight on it to make sure it really is that low. I don't want to have to start driving my mustang to work again with gas prices the way they are, but I also don't want to destroy the MR2 engine. It doesn't burn oil and passes a leak down so I don't understand how the compression could be that low without some sort of indicator. It has 170,000 miles on it so and is just for commuting so should just hone it and throw some rings in it?

Jackstand Queen · 08-20-2009, 09:41 PM

Try running the test with a warm engine. Its OK to add a dozen drops of motor oil in each cylinder just before the test. That's not cheating, but it will get you the very best number possible.

If 120 is your true number, I would expect the engine to burn oil, and really not spin that motor up very quickly.

If you suspect your compression gauge is out to lunch, borrow one for comparison. But they are such simple gadgets, that even the one's made in China probably function well enough.

The bleeding air from the cooling system procedure and not knowing about it has caused literally thousands of blown headgaskets! This one issue is probably the very worst aspect of the first Generation Mr2's.

Dave In Indy · 08-21-2009, 09:30 AM

Well, the car is better on the acceleration, and now the hesitation is almost gone. It's still there a bit, but not as bad. I retested with another gauge and compression was around 170 in all the cylinders so I'm guessing the motor is good. I got the air out of the front two bleeders, but the handle off the engine bleeder. I'm hoping just bleeding the front two will get the job done for the time being. The intake is coming off this weekend for a cleaning.

toy4tao · 08-21-2009, 10:00 AM

What year is your mr2?

edit:nvm i thought yours was mk2

08-13-2009, 02:50 PM	#1 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Engine Hesitates My engine hesitates between 3500 and 4500 r.p.m. and starts rough. I have replaced the fuel filter, air filter, all ignition components, the ECU, the catalytic converter, and the O2 sensor. The only codes I get are 5 and 1 which means no code set. My guess is it's either the timing, a clogged injector, or a bad EGR valve. The car doesn't smoke or anything so I don't think it's a compression issues. It revs fine to 3,500 r.p.m. and quickly revs up after 4,500 r.p.m. and on. Everything inbetween that zone is a dead spot and it is kindy of jerky as it revs in that area. Anyone ever seen this.

08-19-2009, 08:56 AM	#9 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	I'm leaning towards a vacuum hose at this time, but I haven't pulled the intake yet. I'm planning to do it this weekend. The bog has gotten a little worse and is now 2500-4000 r.p.m. area. The car revs fine when it's not under load and even in first gear. As soon as I hit second is when the bog starts getting noticeable. Also it does not seem to bog for the first couple of minutes until it warms up. And the transmission does not want to go into first or reverse when it warms up. It is a manual and did not do that before the clutch was replaced. I don't know if they are related or not. To recap what I know It is not the EGR system It is not the AFM It is not the timing It is not the injectors It is not the PCV system It is not the TPS I'm pretty sure it's a dirty intake which I'm going to mess with Friday night. I also bought new vacuum hoses to put on it. Last edited by Dave In Indy; 08-19-2009 at 12:23 PM..

08-20-2009, 02:08 PM	#14 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Found the majority of the problem, I had a plug with a cracked insulator, and they all look like they got hot. The engine compression was 120 in all cylinders which thrilled me. I went colder on the new plugs and platinum. I had NGK BCPR5ES11 in there now I have NGK BCPR6EGP plugs in there. With the plugs in it seems okay so far though I won't know until I drive home tonight. I'm thinking there may be some air in the cooling system because the engine feels very hot. I'm crossing my fingers it's good to go. Here's a pic of what I found on the one plug. Attached Thumbnails

08-21-2009, 10:00 AM	#20 (permalink)
toy4tao Some Skills Join Date: Mar 2009 Posts: 57 Thanks: 2 Thanked 2 Times in 2 Posts iTrader Rating: (1/100% )	What year is your mr2? edit:nvm i thought yours was mk2 Last edited by toy4tao; 08-21-2009 at 03:48 PM..

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08-13-2009, 03:40 PM	#2 (permalink)
Indysw20 Noob for now Join Date: Jul 2009 Location: Indianapolis Posts: 53 Thanks: 8 Thanked 4 Times in 4 Posts My Google Map iTrader Rating: (0/0% )	Have you done anything new to the car Service, Mods, Weather? When did you replace all the listed items? Im not sure about the EGR i had a avalon that had an egr problem that would jump from 2 to 3 rpm, i had a mazda and it wanted to stall out with an egr problem..DIrty throttle? just throw stuff out there.Im on ss of indy if you need help or what not

08-14-2009, 08:22 AM	#3 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	I replaced everything over the last two weeks. I have even swapped this engine out of one car into the other so I've eliminated anything to do with the fuel tanks computers and the like. I retimed it last night and it is still doing it. I cleaned the throttle and that didn't help. I'm going to pull the injectors this weekend and clean them. The EGR is so rusted up I'm afraid I'll have to break the hoses to get it off.

08-14-2009, 02:48 PM	#4 (permalink)
mr2tim SUPERcharZed ToyZ RacZer Join Date: Mar 2008 Location: South Florida Posts: 1,789 Thanks: 8 Thanked 118 Times in 111 Posts My Google Map iTrader Rating: (6/100% )	If you have swapped out the engine the TPS and the AFM meter were also replaced without change in conditions? If so, perhaps you should run continuity checks on all 7 wires from the AFM connector back to the ECU in the trunk. Concentrate on Vb, Vc and Vs circuits. Pm me for BGB pictures if needed.

08-15-2009, 11:43 AM	#5 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Alright, I replace the AFM with a know good one, and it still did it. So I checked all the vacuum hoses and valves associatted with the emmisions system. Plus I changed all the filters in the emmisions system. Then I pulled all the injectors and cleaned them. They all looked good except the cold start was covered in oil and goop from the PCV hose being upstream from the injector. It still is sluggish and jerky through 3500 to 4500 r.p.m.s. I'm thinking maybe it has something to do with the TVIS system possibly. What does the TVIS do? It seems as if the car is just out of time within that R.P.M. range. I'm sure someone has had this problem.

08-15-2009, 01:07 PM	#6 (permalink)
Allmotor87mr2 Island Auto Warehouse Join Date: Aug 2009 Location: Redlands, CA Posts: 16 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	the tvis (Toyota Variable Induction Syatem) has 8 intake ports going in to the head it only uses 4 of them till a certen rpm than a vacuum actuator opens the butterfly valves than all 8 open. it could be that your butterflys are gumed up and geting stuck or something. the best way to clean it is to take off the manifold and clean it out with amsoil manifold cleaner or some kind of carb cleaner. blow dry and instll its something to try. make sure your vacuum actuator on the manifold is worken. let me know if that dosent work.

08-16-2009, 12:29 PM	#7 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	I second Allmotor87's diagnosis about the faulty TVIS gadget.

08-17-2009, 10:18 AM	#8 (permalink)
Allmotor87mr2 Island Auto Warehouse Join Date: Aug 2009 Location: Redlands, CA Posts: 16 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	yea its probley that ive had that problem before. my vac hose was cracken and my manifold was dirty as .... if it dosent work ive got a few other things you can try.

08-19-2009, 05:12 PM	#10 (permalink)
Allmotor87mr2 Island Auto Warehouse Join Date: Aug 2009 Location: Redlands, CA Posts: 16 Thanks: 0 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	yea it should be that. the reason its prob worse when the engine is warm is the dirt and oil in the mani get gummy causeing the butterflys to stick. i hope cleaning it solves the problem good luck.

08-20-2009, 08:46 AM	#11 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Well, I found a few other issues. I pulled the plugs and did a read. 3 were white and orange colored, and one was black and oily. These plugs are less then a month old. There is a lot of oil leaking from the valve cover into where the plugs are at. I think the plugs might be he wrong temp range, or the gap is wrong. So I'm going to try replacing them again.

08-20-2009, 10:04 AM	#12 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	I'd put money on a broken ring, or leaky headgasket related to the odd spark plug. It looks like it might have to go under the knife to me. Open her up, like a Can O' Beans.

08-20-2009, 02:49 PM	#15 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	120 PSI seems low to me. I had a Jspec N.A. engine that had all cylinders in the 195 to 200 PSI range.

08-20-2009, 03:22 PM	#17 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Sorry I thought 120 was normal. I just read the book and it said 179 to 149. So that is not a good thing. It is a Harbor Freight gauge so I'm taking it with a grain of salt. There is a lot of air in the cooling system so I'm going to bleed it out before I leave today. I had no idea there was a bleeder, needless 3. I'm going to run another compression test tonight on it to make sure it really is that low. I don't want to have to start driving my mustang to work again with gas prices the way they are, but I also don't want to destroy the MR2 engine. It doesn't burn oil and passes a leak down so I don't understand how the compression could be that low without some sort of indicator. It has 170,000 miles on it so and is just for commuting so should just hone it and throw some rings in it?

08-20-2009, 09:41 PM	#18 (permalink)
Jackstand Queen Cage Fighter Join Date: May 2008 Posts: 840 Thanks: 75 Thanked 64 Times in 60 Posts iTrader Rating: (1/100% )	Try running the test with a warm engine. Its OK to add a dozen drops of motor oil in each cylinder just before the test. That's not cheating, but it will get you the very best number possible. If 120 is your true number, I would expect the engine to burn oil, and really not spin that motor up very quickly. If you suspect your compression gauge is out to lunch, borrow one for comparison. But they are such simple gadgets, that even the one's made in China probably function well enough. The bleeding air from the cooling system procedure and not knowing about it has caused literally thousands of blown headgaskets! This one issue is probably the very worst aspect of the first Generation Mr2's.

08-21-2009, 09:30 AM	#19 (permalink)
Dave In Indy Some Skills Join Date: Jun 2009 Posts: 61 Thanks: 1 Thanked 3 Times in 3 Posts iTrader Rating: (0/0% )	Well, the car is better on the acceleration, and now the hesitation is almost gone. It's still there a bit, but not as bad. I retested with another gauge and compression was around 170 in all the cylinders so I'm guessing the motor is good. I got the air out of the front two bleeders, but the handle off the engine bleeder. I'm hoping just bleeding the front two will get the job done for the time being. The intake is coming off this weekend for a cleaning.