420A Hesitation

[AM2SS]

My stock 99 2.0 Eclipse GS has a hesitation when starting cold and during acceleration. It has new injectors, fuel pump, both throttle body sensors, EGR valve, 2 new valves, plugs, wires, coil pack, cam shaft position sensor timing belt and all the gaskets for a timing job.

I'm getting a lean condition code P107 I think. Oh and tomorrow Oct the 27 I will be picking up my fuel pressure regulator. Any ideas?

 

[pauleyman]

why don't you start with the lean condition code. Was all that work done at the same time? If so look for leaks. How does the car idle?

 

[AM2SS]

why don't you start with the lean condition code. Was all that work done at the same time? If so look for leaks. How does the car idle?

All the work has been done over a few months and she purrs like a kitten. I just put in a new fuel pressure regulator yesterday and still have the same lean condition.

 

[pauleyman]

P107 is not a lean code. It's a MAP code

 

[AM2SS]

P107 is not a lean code. It's a MAP code

Well damn, I will put the reader on it tonight and double check the code and let y'all know.

 

[AM2SS]

P107 is not a lean code. It's a MAP code

Yep, it is a p0171 lean bank 1

 

[pauleyman]

Is the o2 sensor working?

 

[AM2SS]

Is the o2 sensor working?

It is not throwing a code

 

[AM2SS]

It is not throwing a code

And I pulled re gapped the plugs too, that seems to have made a little difference

 

[AM2SS]

Is the o2 sensor working?

It is not throwing a code, I sprayed carb cleaner at everything I could think of that would be sucking air, and nothing, I unplugged the map sensor and it died, I regapped the plugs to .35 and helped a little.

 

[BLACK'98DSM]

I recommend a 0.048" plug gap. It runs most efficiently and idles smoothly there. In the FSM, Mopar recommends a 0.048"-0.053" plug gap.

If reducing your plug gap seemed to help with the issue, I'd assume a fueling issue. I've also found that aftermarket ignition coils are always questionable. The OE coil is far superior until failure.

This could also be a small vacuum leak or clogged fuel filter.

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[AM2SS]

I recommend a 0.048" plug gap. It runs most efficiently and idles smoothly there. In the FSM, Mopar recommends a 0.048"-0.053" plug gap.

If reducing your plug gap seemed to help with the issue, I'd assume a fueling issue. I've also found that aftermarket ignition coils are always questionable. The OE coil is far superior until failure.

This could also be a small vacuum leak or clogged fuel filter.

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Thank you for the information I will re gap my plugs, it has a new fuel pump new fuel pressure regulator and a new fuel filter. The coil pack is new and from O'Reilly's.

 

[AM2SS]

Thank you for the information I will re gap my plugs, it has a new fuel pump new fuel pressure regulator and a new fuel filter. The coil pack is new and from O'Reilly's.

Well I set my plugs to your suggested specs both of them and it got worse I dropped it down to .030 and it got way better.

Again I've got a new fuel pump brand new fuel filter brand new fuel pressure regulator and brand new injectors but if the company screwed up and sent me the turbo injectors could that potentially screw things up?

And when I played with my fuel rail both times could there be air bubbles in it making it act dumb or is that just dumb?

 

[BLACK'98DSM]

You'd be having the opposite issue with turbo injectors. Too rich in that case, not too lean as currently. But those aren't interchangeable anyway.

Increasing the plug gap made the issue worse because you're now getting a more thorough burn in the combustion chamber, which is causing the O2S to read even leaner than before. Just because changing the gap didn't fix the issue, that doesn't mean you should change it back. The ones I have posted are the correct specs and should be used.

You now see the problem with throwing parts at something instead of actually diagnosing it. You probably didn't need any of those parts.

I'd start with checking fuel pressure at the rail and move on from there.

 

[AM2SS]

You'd be having the opposite issue with turbo injectors. Too rich in that case, not too lean as currently. But those aren't interchangeable anyway.

Increasing the plug gap made the issue worse because you're now getting a more thorough burn in the combustion chamber, which is causing the O2S to read even leaner than before. Just because changing the gap didn't fix the issue, that doesn't mean you should change it back. The ones I have posted are the correct specs and should be used.

You now see the problem with throwing parts at something instead of actually diagnosing it. You probably didn't need any of those parts.

I'd start with checking fuel pressure at the rail and move on from there.

10-4 I will check the specs in my Haynes manual perform the test and post the results, thank you for your help.

 

[AM2SS]

10-4 I will check the specs in my Hanes manual perform the test and post the results, thank you for your help.

Well I went to O'Reilly's borrowed their fuel pressure testing kit and the reading was between 48 and 52 PSI nice and strong but the bleed down is not immediate but it failed the 5 lb per minute drop..so I got the Haynes manual inside and going to see what's next on the list.
And on top of this I still can't fill the fuel tank without going stupid slow or keeps stopping so there's check balls and check valves and maybe hoses I might need to replace. Could that be part of the issue not sure new to JDM vehicles.

 

[AM2SS]

You'd be having the opposite issue with turbo injectors. Too rich in that case, not too lean as currently. But those aren't interchangeable anyway.

Increasing the plug gap made the issue worse because you're now getting a more thorough burn in the combustion chamber, which is causing the O2S to read even leaner than before. Just because changing the gap didn't fix the issue, that doesn't mean you should change it back. The ones I have posted are the correct specs and should be used.

You now see the problem with throwing parts at something instead of actually diagnosing it. You probably didn't need any of those parts.

I'd start with checking fuel pressure at the rail and move on from there.

Well, reading my manual it sent me to vacuum leaks I checked all my vacuum hoses up front and I found my I think evap ventilation solenoid on the passenger side all the way forward in front of the wheel well liner behind the front fascia it was just hanging loose flopping around I remounted it cranked up the car check engine light went off but the car ran like hot garbage, I drove it around real slow through the neighborhood a little bit and went to give it some gas and it took off like a scalded dog she ran great but it sit for 24 hours back to hot garbage with the check engine light on WTF.

 

[AM2SS]

Well, reading my manual it sent me to vacuum leaks I checked all my vacuum hoses up front and I found my I think evap ventilation solenoid on the passenger side all the way forward in front of the wheel well liner behind the front fascia it was just hanging loose flopping around I remounted it cranked up the car check engine light went off but the car ran like hot garbage, I drove it around real slow through the neighborhood a little bit and went to give it some gas and it took off like a scalded dog she ran great but it sit for 24 hours back to hot garbage with the check engine light on WTF.

Update, I did a smoke test on the vacuum system found some small leaks repaired those but one leak I'm not sure if it's no big deal or what I should do but smoke was coming out of the dipstick tube it has a rubber plug on it but apparently that rubber plugs not working anymore do I need to find a new one or is this no big deal ? and hopefully my map sensor should be here soon.

 

[99dsmer4g63]

Sounds like it’s your ECT sensor for the ECU.

Plug in a scan tool that has live data and see what the coolant temp is while the car is cold. It should be close to ambient air temp. Watch it closely as the car warms up and see if reacts the way you would think it should.

There also might an ohm range to check the sensor is okay. Could be the wiring to it as well and not the actual sensor.

-Daniel

 

[AM2SS]

Sounds like it’s your ECT sensor for the ECU.

Plug in a scan tool that has live data and see what the coolant temp is while the car is cold. It should be close to ambient air temp. Watch it closely as the car warms up and see if reacts the way you would think it should.

There also might an ohm range to check the sensor is okay. Could be the wiring to it as well and not the actual sensor.

-Daniel

I had a new ECT/w a new pigtail on order before I read your post. That has been installed along with a new MAP sensor and I cleaned the Air intake air temperature sensor. It still has the 171 code and the hesitation. And also with each thing I fix, clean or replace something she runs a little better. Soon I will put it on a scan tool and watch the live data and see if any of the sensors are not talking or out of spec. Thank you for your assistance.

 

[AM2SS]

Sounds like it’s your ECT sensor for the ECU.

Plug in a scan tool that has live data and see what the coolant temp is while the car is cold. It should be close to ambient air temp. Watch it closely as the car warms up and see if reacts the way you would think it should.

There also might an ohm range to check the sensor is okay. Could be the wiring to it as well and not the actual sensor.

-Daniel

I finally got a chance to get this done and it works perfectly. And still has e P0171 code.