Checking Fuel Rail Pressure Optra/Lacetti - help a noob!

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aPLCforYouAndMe
Posts: 1
Joined: Mon Apr 18, 2016 5:40 pm

Checking Fuel Rail Pressure Optra/Lacetti - help a noob!

Post by aPLCforYouAndMe »

Hello,
Let me start by saying: I am waiting for Auto Repair for Dummies in the mail.

2004 Optra LS 2.0L Sedan (Daewoo Lacetti)
No backstory: Is this black twist-off cap where I attach a fuel pressure gauge? What is the proper process for checking the pressure?
Image
http://postimg.org/image/e16zura67
Cap on left side.
Image
http://postimg.org/image/i4q3b760v

Details: Bought my first (used) car a month ago - a used 2004 Optra LS 2.0L Sedan (Daewoo Lacetti). It had 126,300km on it when I got it. I've put about 800km more since then.|
When it starts "normally", the exhaust mix smells rich, and the engine jumps to about 1300rpm and then over 30 seconds slowly goes down to ~900rpm when idle.
All fluid levels were topped up by the dealership - I checked with the help of an experience family member.

At first - it wouldn't start easily when left out in the rain and unused for over 5 hours, even damp weather. The car would take anywhere from 2-10 tries to start. The starter always spun up, and then it would shake violently, try to rev, and die. Eventually it would start, but it would shake a lot at first for a minute or so, and when I idle forward (no pressure on gas pedal), it would "lurch" instead of roll smoothly.
Then it stopped happening once the weather got dry, a little while later it rained, and surprisingly it did not have any issues.

Then two weeks ago it wouldn't start, in dry weather. Tried ~10 times, and at first the engine rev'd a little bit (maybe 500rpm) and died. By the 10th time trying to turn the key, I had tried spraying the spark plug contacts & cables with silicon spray. No difference. I decided to check if the fuel pump was turning on, so I opened the gas cap, had my girlfriend start the car, and it turned right on. It was warm overnight, and got cold in the morning - i figured negative pressure in the gas tank was the problem - maybe the gas-cap wasn't venting properly.

No problems for a couple of days, and then it would shake when I start it up, the engine rpm would flutter between 300-900rpm, jump to ~1300rpm, and then slowly go back down to 900rpm (normal operation) when idle.
Yesterday (after it sat unused for ~24 hours) I tried twice to start it - turn the key, engine flutters at low revs, then dies. Then I opened the gas cap for a second, shut the gas cap, turned the key and gave it some gas when I started, and it started up. 2 Fault codes appeared: P0703 - Torque Converter/Brake Switch B Circuit (which has come up before intermittently) and P02BF - no information on web available.
However, it's been rev'ing low when I start it since then whenever I let it sit more than 6 hours or so, and I generally give it a bit of gas to make sure the engine doesn't die on startup.

How should I trouble-shoot this? Does it sound like a fuel pump issue?
Much annoy.

Thanks for any help!
exist3nce
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Posts: 1233
Joined: Mon Oct 25, 2004 2:24 am
Location: Toronto, Canada

Re: Checking Fuel Rail Pressure Optra/Lacetti - help a noob!

Post by exist3nce »

Hello there.. sorry to hear about those issues. That little cap on the rail can be removed to reveal a small valve that you could connect a pressure gauge to. It resembles a tire stem valve, but I don't know exactly what type of fitting or connector you need to be able to attach to it.

It doesn't really sound like fuel pump to me though... although it would be nice to confirm by attaching a pressure gauge so that when it is not starting you can at least verify proper pressure (which should be around ~44psi). Sounds more like an electrical issue, especially since you mention it happens more when its damp. I have a manual, so no experience with the auto - but I have heard many other complaints about issues with it. Unfortunately those codes don't tell me very much. The only issue I've had that resembles this is when my camshaft position sensor was going bad... it would stumble really bad on startup, but only sometimes. Others have had this issue too - watch for any cam related codes.
2004 Optra/Forenza/Lacetti - 225whp - Haltech Sprint500 - CT12B - Getrag F28 6spd - KW V3 Coilovers - FX35 Retrofit
2002 IS300 5MT - 615whp - AEM EMS - GT4088R - Built 9.5CR - R154 - TRD LSD - SupraTT T/B - Varex - LS430 Retrofit
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