Need Diagnostics Help - OK's Tom

[blackws]

I need help diagnosing my 1999 Honda Civic GX. Would OK's Tom or some other good GX diagnoser contact me. Currently produces way less power while in higher fuel usage situations (climbing mtn pass or trying to maintain 75 mph on UT freeways - small up and downs - still can get up to 85+ but takes much further than before); Also occasionally loses all power (much like a gasoline vehicle running out of gas - or vapor locking - not gotten to the point yet of completely stopping and sitting....). Can someone tell me if there is a throttle position sensor, O2 sensor or anything else I can troubleshoot to fix this (would also need the troubleshooting steps).

[freedml]

Re: Need Diagnostics Help - OK's Tom

First things first, hook up a code reader/scanner. Some performance problems don't turn the Engine Light on but will store a misfire code, like injectors or coils. Then I'd change the fuel filter to see if that helps. If you've never had either of the pressure regulators fail, you might be needing one soon.

[blackws]

Re: Need Diagnostics Help - OK's Tom

Freedml, Thanks for the reply. Previously had misfires and have had 2 injectors rebuilt (and flow tested) [other 2 failed and were replaced with non honda {at $400 each I just could not afford it} injectors] and had just replaced air filter. I will hook it up to a scanner again (last time was why I rebuilt the injectors - an Autozone employee said this time that 'since my check engine light was not on, I was not to waste their time'). Changed the fuel filter (just the one because 1999 ) last Sat. Plus this doesn't feel like a single cylinder issue, with misfiring you could feel it, this is an overall loss - more like starvation [fuel, air, and ignition] - (spark is usually a single cylinder - though of course it could still be the computer), Air flow should be good (just replaced the air filter, but will check the intake tubing again); leaving pretty much fuel flow.... I would not doubt that I might need to replace a regulator or anything else; but would appreciate diagnostic recommendations and steps for such....

[freedml]

Re: Need Diagnostics Help - OK's Tom

If you have good pressure and flow at the fuel rail, then I would suspect injectors or coils. I would also wonder about those non-Honda injectors.

Then I would turn my attention to the HPR.

[Lakewood90712]

Re: Need Diagnostics Help - OK's Tom

I would be very surprised to find non oem cng injectors available. I suspect someone sold you gasoline injectors . many times the parts interchange info is flawed and may say "Fits all '99 civic". I've even seen a interchange guide showing the gasoline fuel filter fitting the GX. If that is the case , better get it fixed fast before you burn up one or both catalists ,($$$$)

[wjdaytech inc.]

Re: Need Diagnostics Help - OK's Tom

did you overlook the mech of the engine itself? do a cranking vacume,run vacume test, could be a timing belt issue, etc. bottom line its always better to hire a pro that is trained in the field.

[blackws]

Re: Need Diagnostics Help - OK's Tom, etc.

freedml, not really sure of the pressure at the rail - know of an available guage that I could either check it with or better yet, permanently install?

lakewood90712, yeah - I hear what you are saying... I contacted Autozone and told them that the repair instructions they had posted for the GX fuel system would kill someone. They got back with me and said that they would (as far as possible) correct their Honda repair instructions to differentiate between gas and CNG.

here are the injectors rockauto showed:
AIRTEX Part # 4G1299
MPI; 06164-PDN-J00
for HONDA CIVIC GX (1999 - 2005)

STANDARD MOTOR PRODUCTS Part # FJ327 {INJECTOR}
for HONDA CIVIC GX (1999 - 2004)

So these 2 manufacturers vary on which years they claim the injector fits in, but not by much and they don't cross list it with any other honda vehicles.

Any way, I got 2 of the airtexs (and WOW! They have been marked up 230% from when I bought them less than 6 months ago).

That is something I DON'T like about honda parts, nearly impossible to find any information about what other vehicles a part fits on - once the dealer finds the part, they cann't even check what other vehicles use the part (ie - one can not find a wreck of another year and pull parts without talking to an extremely KNOWLEDGEABLE person........ as if you can even find any GX parts available in a wrecking yard anyway)

wjdaytech, what ever. Ken Garff (as far as I can find) is the only GX Honda certified location in northern UT (100 miles away) and Honda won't even let HIS mechanics in HIS other locations certify (thankfully one of these others [only 50 miles away]was at least knowledgeable enough to look up the fuel filter and sell me that - when my local dealer was quoting the price for the entire pipe assembly - and stuck by it - when I told him that I only wanted the filter; so I politely told him thanks, and talked to the 50 mile away Ken Garff dealership [who's parts person was a mechanic which had studied all the GX materials, but wasn't allowed by Honda to test]). Btw, I am a licensed and certified Airframe and PowerPlant mechanic - I also have purchased training materials for ASME's CNG certification (just haven't bothered testing on it. I have heard of some CNG aircraft engine conversions; but....). I have also maintained all my own vehicles (and my parents vehicles, until I moved from home) from when my father taught me until now.

[artbros]

Re: Need Diagnostics Help - OK's Tom

Blackhawk... you and I need to talk. Sounds like we have the same problem.

I have a 99 GX. I've recently observed signs that my FPR may be failing. The vehicle works well enough if operated on flats with little call for quick acceleration. Get on steep hills and speed cannot be maintained. The engine bogs down and fails to maintain power. Interestingly, the temperature guage rises when this happens.

In the past, the power loss indicated bad injectors (and the temp never rose). Cleaning them or replacing a bad injector has fixed the problem. In this case, there is no obviously bad injector. It is possible that partial plugging of the entire bank of injectors could be the culprit, but it seems unlikely.

I pulled the plug on the fuel filter and found a tiny bit of condensation. But nothing to write home about. Filter looked like new.

So, the problem is likely either a clogged cat or a problem with fuel delivery.

For what it is worth, I have learned that injectors used on the GX have HUGE flow rates. When building high performance or racing engines, mechanics often turn to CNG injectors (or from Mazda Wankels). When compared with gasoline injectors the volume that passes through CNG injectors is tremendous. Therefore, the post from the individual suggesting that you may have installed a gasoline injector does not deserve much merit. If the injector fit the hole (unlikely) the body of the injector could not have equaled the through-put of a CNG injector and your car would have run worse, if it ran at all, with gasoline injectors.

As to Honda parts, I've gotten superior service from DCH Honda in Temecula CA. Mike Cobain runs the internet side of sales. He is very helpful. Great attitude. Fast delivery. Great prices. Helpful in every way.

Garff in SLC has proven to be less than spectacular. Parts are often not in stock. Prices are not negotiable. They seem offended that any other Honda dealer would sell parts at a discount. Their service writers don't listen or they don't communicate with the techs. (They now have two techs with a third in training.) Because they don't communicate, they repeat procedures that have been performed (and charge you for it), and then tell you what you already know (and expect you to be grateful to them for stating the obvious). They may have improved since last year, but the last time I darkened their door they seemed to gravitate to the school of "jack up the radiator cap and slide a new car underneath." Replace parts until the problem is solved.

Singularly unimpressive.

Anyway, I'd appreciate your thoughts or progress on the FPR or cat issue. It is possible, I suppose, that the cats are clogged or damaged. But a visual inspection of the upper cat (by removing the upper sensor) indicates that the brick is intact and appears not to deformed or melted into a solid lump of molten fiscal pain.

I'm about ready to pull the injectors and send them out to be cleaned. Wish there was a local shop that could do it. So far the best shop I've found is in Arizona. $17 per injector. With all the CNG going on in Utah it seems like a business whose time has come.

If you'd be so kind, please post here (so all can benefit) AND drop me an email: [email protected]

[blackws]

Re: Need Diagnostics Help - OK's Tom

hooked it up to the scanner, but nothing detected. I will begin working with a friend which has access to shop support. Wish I'd gotten more diagnostic type help here (like expected electrical voltage, resistance, etc across certain connections to determine if it is a pressure valve, O2 sensor, throttle position - if this vehicle even has such a sensor - etc.).

artbros, did you have a link for the internet sales side of the CA dealer?
Definately going to discuss issues with artbros on and offline....

[Curtis]

Re: Need Diagnostics Help - OK's Tom

Blackws, just a suggestion, but you may want to order a shop manual for the car. There's a link in "Helpful Links" to Helms Inc. top left side bar.