I am just suffering problem after problem with my car. 91 race built engine in 95 GSX. I was driving today, launched and got into boost and then settling down to cruise speed the car started missing, rpm's going down while driving, the car bucked a couple of times. I pulled over turned off engine. Checked engine, timing marks the same so timing belt did not move, checked axles thinking I broke one, its fine. Turned engine on and runs fine. So I am close to destination and got into boost again a little and slowed down to intersection, turned and she dies on me. Pulled into station which I was lucky was close. Started engine agian and she turns over and runs, oil pressure good, but she just shakes over and over, the engine. Towed the car back home. Put in new spark plugs thinking the other ones fouled. The spark plugs definetly fouled and look terrible. I was using autolite 63 and never had problem when using 92 octane, but ever since using c16 have had problems. Finally got the BPR7ES NGK today after ordered 3 days ago and threw them in thinking the spark plugs are fouled so this is the problem. Same problem, It starts, but engine runs and just shakes. What is going on? I have crankwalked a 2g engine and rod knocked a fully built 2g engine years ago before and when that happend all check engine lights came on and it sounded like metal hiting metal, but this is different. Now I have fully built 1g engine. Any ideas of course of action. I am afraid to start engine again. I think I internally did damage. Definetly fouled the shitty autolite plugs, but replaced them with NGK new ones and still engine just shakes and rpm says .25 or almost no rpm. Any help or response will be appreciated.

Did a intercooler pipe come loose or come off.
Joe

Who built the engine?

isnt that a symtom of crankwalk?

I doubt its crankwalk... But who knows... I woudl check the simple stuff first. Leaks, timing (you mentioned its fine but see what timing is), What kind of intake are you using? Maft? 2g mas? Give us more info

The bottom end is stage 3 magnus motorsports and cylinder built by D & G Motors here locally in Twin cities. Probably is crankwalk. This is a dahm 1g engine though. I have read only one case of 1g engine crankwalk. I guess I will take off sump and see what happend. I am using 2g mas and injen intake. If I remember crank walk sounds horrible. Like metal rubbing against each other. I can start engine, but there is no rpm and tach and if I put peddle down no rpm, but the engine is rotating. and runs. I have had silicone hoses for intercooler come off before, but then engine does not even start.

Check your ic pipes and make sure that your MAS plug is connected all the way. I had the same stuttering problem on my car but it went away after one day (so far so good). With an ic pipe blown off, the car should still start. I have done it several times. The car jsut runs like shit. Do a boost leak test. I have made several boost leaks on my new setup. I think I have them all fixed good enough now.

God, I hope it is maybe a boost leak. The car started halting and missing after the heavy load from boost in second and third when I was slowing down. I checked connection for mas right after, and the i/c connections, but I am going to do it again. I just have bad feeling about the way everything has gone down here. HAS ANYONE RUN INTO PROBLEMS RUNNING C16. Does it cause problems to oxygen sensor, it has caused plugs to foul? I am not running anymore boost (20psi) then before. I had planned to re-tune and turn it up later. I am just pessimistic and lost. This has been a painful start for me so far this year and it looks like the end for me too. No way I can afford another engine until maybe winter. Too many problems and hours on the car.

C16 is a leaded gas and will foul plugs, also it can adversely affect the O2 sensor, but I don't think it woul djust stop working? What do you use to tune, check what your O2 sensor voltage is...

Chris

I use dsm link for fuel WOT, global and dead time and use dsm link to add timing. I have checked allot of the basic stuff. I'll check voltage for o2 before I start engine tomorrow. When I start engine I'll check oil pressure and rpm immediately. Same situation, I will turn off. One theory I have is maybe the new cylinder head has a loose valve, broken guide or something. Just spent allot of money on a new head. Ferea valves 1mm, dual valve springs, titanium retainers, new seat locators, guides. I'll remove cover and turn crank pulley enough revolutions and see what the heck. Again nothing happend to timing belt and tdc lines match. I plan to remove sump too after valve cover if I see nothing from where I'm standing. Its been a long time since I checked end play for crankshaft. Anyone know specifications for 1g 1991 2.0? I think .00200.0070 in. Any suggestions on what else I can do with sump off to check engine? When I rod knocked 2 years ago I was able to see damage. Appreciate the help from everyone! Hope I don't have something major on my hands, but if I do hopefully can afford new engine by winter.

Could do a compression test, if one of the valves isn't functioning correctly that would show in the test.

Chris

Your right. Thanks for the idea. I am going to do that first before remove valve cover. That would reveal something wrong. All I know is timing belt is not issue, but could still have engine failure, majorly. I had 160 all four cylinders before when assembled. Hypothetically if I see any one of the chambers lower, it would have to be allot lower if a valve is not opening and closing, right? I have had compression check done a few times, but this is new engine.

Thank You to everyone. I did compression test and 160 all four cylinders. C16 adversly effects o2 sensor, so I am going to go through allot unless I tune to 92 octane. I am stupid and tuned the car on dyno to only C16 this year. Also I am going to go through spark plugs on a regular basis using c16. Warning to anyone using c16. Safe anti knock fuel and car will not pull timing, more power, but check plugs and o2 every short while. I know probably everyone knows this allready, I learned the hard way.