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| Hesitation on acceleration; Hesitation on acceleration | |
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| Topic Started: Feb 7 2010, 10:45 AM (682 Views) | |
| acehi | Feb 7 2010, 10:45 AM Post #1 |
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Hello everyone, I have a problem I have been trying to tackle for several months now and it is driving me crazy that I haven't fixed it yet. I have read several posts on here over the past couple weeks and double checking the work I have done but still no luck. Some posts on here sound familiar to my situation but I wanted to get a little more in-depth on what I have done with hopes that someone can guide me in the right direction. Now, I am in the military stationed in Korea so I don't have access to Autozone and other specialized equipment here. The best diagnostic equipment I have readily available are: voltmeter, timing light, my hands, nose, and ears.  I also have my haynes manual.Anyway, I have owned this car since 1999 and I have done all maintenance on it myself. I rebuilt the engine in 2003 when it had 160K miles on it because the #2 piston shattered. I bored it out and put +.030 pistons in it and all other internal parts looked great. Two years ago I rebuilt the cyl head because the seals were leaking and all looked good at that time too. About a year ago I started getting this hesitation/bogging when I try to accelerate and since then it has gotten worse. I have 230K miles on it now. About 5 years ago I was getting 52 MPG on average and now I am only getting 38 - 40 MPG. The hesitation happens on a cold or warm motor. It will only have the hesitation when under a load, if I am just sitting in neutral pushing the gas pedal it runs fine. On startup the motor sounds like it is running on 2 cylinders and after it warms up a bit it smooths out. I have also noticed on startup I will smell gas for about 30 seconds then it goes away. My #1 spark plug is black in color and the others are still white, no damage to them. Here is everything I have replaced (new parts not used) so far with no luck. I have changed all the vacuum hoses, new fuel pump, new fuel filter, new fuel injector, new fuel pressure regulator, new TPS, new plugs, new plug wires, new cap/rotor, new coil, and new O2 sensor. The catalytic converter was replaced in 2005 and the muffler system replaced early last year. I have also done several other things to try and find the problem. I have taken the EGR valve off and cleaned it out completely. I have taken the ex manifold off and cleaned the EGR port all the way thru. This port was completely plugged back in 2003 when I did the rebuild but this time it only had about 1/8" buildup of carbon on the walls and not plugged up. I have disconnected all fuel lines and have blown compressed air thru them and all is clear. I have adjusted the idle and the timing. I pulled the cap off the EVAP canister and the seal is torn slightly. I pulled the canister out and it is completely dry inside as well. I have put the spare fuse in the DIAG slot and I get 12 for my code showing all good. Under the hood on the label it shows the vacuum system layout. I have verified all hoses are hooked up correctly according to that chart. I have pulled the O2 sensor out and ran it that way to test if the CAT might be plugged. Hmmm, trying to think of everything else I have tried. Today I went onto Autozone website and ordered the following items: PCV valve, coolant temp sensor, and temp switch. I will try these items next. While I am waiting for these parts to come in I will keep checking things out. I am hoping it is something simple that I am just overlooking. While reading the chart under the hood on the vacuum system layout, it shows hoses going to the BVSV, VSV, Idle speed control valve. I cannot find any of them online to buy anywhere. I have read about the BVSV and about the purge valve on the EVAP canister and if they are faulty it could lead to problems that sound familiar to what I have. What is the VSV? It isn't even listed in my haynes manual. Also, how would I know if the ECM is actually functioning properly? I am asking this because after I installed my new TPS I forgot to plug the wire harness to it. I drove it for 2 days and my check engine light never came on. However, when I put the spare fuse in the DIAG slot I will still get a code 12. The only other few items I can think of that could be causing this are the BVSV, purge valve, plugged CAT, something clogged inside my intake. Does anyone know where I can get a BVSV, VSV or an Idle speed control valve? And what price they would be? Is there anything else I should look at? I have read my haynes manual from front to back and tested just about everything I was able to test that could have been related to this issue. Any help would be greatly appreciated. Jeff Edited by acehi, Feb 7 2010, 10:57 AM.
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| juggalo_joker89 | Feb 7 2010, 11:10 AM Post #2 |
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New Member
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wow....I'm having the same problem. I'm trying to find out from the previous owner what he did to make my car "just start" to do this. If you figure it out do post what it was, cause I'm boggled by this myself. |
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| carmech97 | Feb 7 2010, 11:41 AM Post #3 |
Backyard Mechanic
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How is the compression on that? |
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| acehi | Feb 7 2010, 11:50 AM Post #4 |
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New Member
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I don't have a compression gage to test it here. All my tools are back in Michigan.  I am trying to find a korean automotive shop around here that might understand english and could test it for me.
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| mwebb | Feb 7 2010, 09:29 PM Post #5 |
 
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if you bought some test equipment instead of throwing parts at it you would be way ahead of the game imho have you voltage drop tested the grounds yet ? have you connected the DVOM to the 02 sensor to see if you are in fuel control or pinned rich or lean at the time of the problem ? see the how to section in this forum for the voltage drop testing provide voltage at the 02 sensor signal at hot idle 2k rpm time the problem happens 02 sensor should always be cycling from 150mv to 850mv should cycle in 100ms at 2k rpm , but with a DVOM you can not see that test do not guess post your results |
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| acehi | Feb 8 2010, 03:08 AM Post #6 |
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New Member
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I don't want to buy a bunch of new equipment when I already have all this equipment back home. I have been in the Air Force for 22 years now and I retire in 122 days. I just want to get this car running good before I ship it back to the states. I think I fixed the hesitation problem today.  I went into work today and pulled my car inside the shop. Since I work in a machine shop and welding shop I have a nice drive-in bay to work in. I pulled the EGR valve out today and started the engine. It sounded like I pulled my O2 sensor out but then it started surging really bad until I put my finger over the hole that had suction and it smoothed out. So, I knew that was good. I put the EGR valve back in and hooked the vacuum lines back up. I looked at the EGR module and I looked at the diagram under the hood and all was hooked up correctly. However, I remember several months ago I took the module out and I pulled the cap off to clean the filter and when I put it back together I didn't know what side was the "P" or "Q" so I guessed. Well, just for the heck of it I turned it around and tried it. I started it up and the EGR valve doesn't move nearly as much when I give it gas. So, I thought I would take it for a test drive. No more hesitation. Now I just need to figure out what is causing my motor to run so rough on startup.I found a compression gage today and I also checked that. My compression was #1=147, #2 = 150, and #3=149... Is that a normal compression for this car? Jeff |
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| Johnny Mullet | Feb 8 2010, 06:47 AM Post #7 |
"Geo Whisperer"
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Those numbers are below the 156 minimum, but it will continue to run for a while like that, but poorly. |
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| enginedoctorgeo | Feb 8 2010, 06:51 AM Post #8 |
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Thanks for serving our country for so many years! May you have a great retirement! (Peace is our profession) bet you seen that a little huh? One question- When you checked compression did the one cranking the engine have the accelerator to the floor? You want to check your compression with the gas pedal pushed to the floor. Edited by enginedoctorgeo, Feb 8 2010, 06:58 AM.
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| Bad Bent | Feb 8 2010, 12:02 PM Post #9 |
Facetious Educated Donkey
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Click: How To - Compression Test. |
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| bogs | Feb 8 2010, 12:10 PM Post #10 |
Duct tape heals all wounds
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Congrats on figuring that out  but yah, make sure you follow the linkie BB posted and that the compression test is done correctly. I still need to complete my own, even though I think my car runs like the bees knees
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| acehi | Feb 8 2010, 10:11 PM Post #11 |
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New Member
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I might have spoken too quickly. My car does run much better but there still is a slight hesitation. I watched him do the compression check and he did not touch the gas pedal at all. He put the compression gage in, and he sat in the seat with one leg hangin out the door and the other pushing the clutch. After he was done he converted it from a metric reading to english. His converting could have been a little off too or it could be off because he didn't push the gas pedal all the way down. Does the compression usually go up or down with the pedal to the floor? Also, would the larger pistons increase or decrease the compression at all? Thanks |
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| enginedoctorgeo | Feb 8 2010, 10:27 PM Post #12 |
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Compression will increase with wide open throttle. Not sure I understand your piston size question. |
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| mwebb | Feb 9 2010, 12:00 AM Post #13 |
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at least as important as compression testing without a leakdown test is intake vacuum at hot idle at sea level should be about 20" BUT the needle MUST be rock steady solid smooth . without any flutter and about 21" at 2k rpm peak at 0" then 25" at WOT snap followed by decel to idle ===============================================  right click on image - select view image - click 2x to expand image with test equipment you can see the hash in the Burn line during WOT snap to indicate leaking valves , as the combustion gases leak by the valve they rush by the spark plug blowing out the flame ..... this 1994 suzuki swift 1.3 G13 had 20" of vacuum with 1/2" of flutter . leakdown test on cylinder 1 and 2 would be bad .... compression may be ok as firing KV looks ok that is not carbon tracking as carbon tracking would go to ground or zero . |
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| acehi | Feb 12 2010, 08:22 AM Post #14 |
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New Member
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I haven't had the compression retested yet with the gas pedal to the floor, but after I do and if it is still low, what would be the best way to build my compression back up? What is the max compression for these motors? If I was to machine anything off the head, what would be the max amount to take off? Thanks |
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| bogs | Feb 12 2010, 10:47 AM Post #15 |
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Duct tape heals all wounds
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I believe (but could be misquoting or mis-remembering) that the original compression was like 200-210, and can be as low as 150 (pretty sure thats correct). If not, someone will be along presently to correct that. __As far as how much you can remove from the head, I believe the guy from 3tech took quite a bit off and still had a non-interference engine, certainly more than .020. I'll have to look through the threads again and see if I can find it. ___As to the best way to build compression up, it depends on where your loosing it. From what I gather, if your dry testing and it comes up low, its the valves your concentrating on. If wet testing, its the piston/rings you need to look at. Going off to look through threads to verify or dismiss what I've said so far Really, its all in here somewhere
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