j9chan

Hi guys, I have a 1998 Si with quite a bit of milage on it (188,500km to be exact). I got it used at the end of last year; the last guy works in Windsor so he commuted a lot.

Since I got the car I've done quite a bit of maintanence to it, putting in a CAI, replaced the gas filter and spark plugs, clutch oil, tranny oil, engine oil, etc.

The problem that I have now is when I hit the gas paddle hard during 1st and 2nd gear. The acceleration would be jerky; over some range of RPM it would be quicker than others.

Does anybody have any idea why that is? Spark plug wires? Distributor cap/rotor? Anything else?

Also, I'm looking to change the PCV valve but I can't find it in my car. Could somebody post a picture of where it is located? Thanks!

Thanks guys!

punkindrublic

bbarbulo will post soon and he is usually right

bbarbulo

iTrader: (2)

I would say you have an intermittent high load misfire. What plug wires are you using, and what is the resistance on them? Does the CEL come on? Cuz it damn well should for a misfire. Does the RPM bounce up and down, or do you notice a lack of power. Could be dirty fuel injectors too... A lot of things that could be wrong.

EKdude

have you changed your Spark plug wires? If so make sure you have the right ones...

imported_JookSingKid

Does this happen all the time or during certain weather conditions.

Did this happen before you did the plugs?

if so, i am thinking then it is your wires, try to get your wires tested before just replacing them. how do the wires feel? are they beginning to get dry? stiffen?

if not, check your plugs for gapping or to see if the plug wires are on properly.

do you have any modifications to the motor?

imported_BoOsTd

could it be a slipping clutch?

bbarbulo

iTrader: (2)

didn't even see that... thanks PID!

punkindrublic

no problem and its the truth isn't it?

bbarbulo

iTrader: (2)

too hard to say over the net, but I can usually point them in the right direction on how a mechanic would troubleshoot it, or I can tell them where to find the info... I'm sure if he had a OBD2 scanner he'd be able to see a pending CEL code for misfires, which would tell him what cyl is having a problem, then switch some wires around to see if the problem moves with the wires, and then he'd know if that's the problem.

j9chan

Guys thanks for all those quick replies! You guys are definitely a helpful bunch. Below addresses a number of things you guys brought up:

- I have no other engine mods other than the CAI.

- the plug gapping should be fine, since they were changed by a pretty experienced garage dude. I think the problem's been there even before the plugs were changed, but I can't be sure.

- the CEL doesn't come on.

- the clutch COULD be slipping, since it's been pretty used. Is there a way to be sure?

- the plug wires are OEM wires but I think they haven't been replaced. I'm getting new ones soon, but I'm not sure if that would fix the problem.

- the problem happens in any weather condition, but is more noticeable when I have my AC on.

Thanks once again guys!

bbarbulo

iTrader: (2)

Any loss of power will be more noticable with the A/C on.

To check your clutch, pull the e-brake and the car should still be able to drive off with the e-brake up relatively firmly.

Other way is... it you can do a smokey burnout and take pictures for us to enjoy, then your clutch is also good

If the plug wires are still original, I would urge you to start there... at least pull them and test the resistance using a multimeter.

j9chan

Hi bbarbulo, is the multimeter the proper way to test the plug wires? What should the resistance be? If the resistance is still very low (whatever that means ), do I still have to replace the wires?

imported_JookSingKid

If these are the original wires since 1998

They probably need to be changed, if not changed in the near future.

bbarbulo

iTrader: (2)

if resistance is low, and you don't get shocked when touching the wires, then they don't need replacing. Rule of thumb is 11K ohms, but I'd say change them if it shows 8000 ohms resitance. Wires on all 3 of my cars are all under 1000 ohms.

j9chan

Do you mean rule of thumb is 1.1k Ohm or 11k Ohm? So to properly test them, I should disconnect it from the distributor cap at one end and the valve cover at the other, then check the resistance for each of the 4 wires?

Thanks a lot!

bbarbulo

iTrader: (2)

that's on the high end... like I said for sure if I see 8K, I'm replacing them...

disconnect one plug wire at a time, one end of multimeter on one end, the other on the other end, observe reading...

j9chan

By the way, I've been using those fuel injector cleaner that goes into a tank of gas once every two months or so, and the RPM doesn't bounce up and down. So I wonder what else it could be. Could it be the valve clearance? I wonder if I should take it in to have that adjusted, but the price is a little steep at $110 including the valve cover gasket change...

bbarbulo

iTrader: (2)

valves get noisy when you first start your motor in the morning. It's got nothing to do with performance.

1st step read your plugs... glazed, carbon fouled, or just a little brown?

2. check complete ignition system INCLUDING TIMING!!

3. Fuel pressure at the rail

4. compression test

5. EGR condition - test system

Not having set a CEL, I highly doubt its anything other than ignition or fuel pump. Test fuel pressure.

ohmstable

I would change the distributor cap/rotor and wires. Most likely lack of spark is causing the hesitation.

Symmetry

I have the same jerky performance problem in 1st only, more noticeable with A/C on too ...

bbarbulo pointed out a number of things, but I noticed the coincidence of him mentioning dirty fuel injectors and the guys at Mr. Lube advising me over the weekend to really clean out part of my fuel system for better performance.

The inspection is free with the oil change. The cleaning job costs $70 there.