Jump to content
View in the app

A better way to browse. Learn more.

300ZX Owners Club

A full-screen app on your home screen with push notifications, badges and more.

To install this app on iOS and iPadOS
  1. Tap the Share icon in Safari
  2. Scroll the menu and tap Add to Home Screen.
  3. Tap Add in the top-right corner.
To install this app on Android
  1. Tap the 3-dot menu (⋮) in the top-right corner of the browser.
  2. Tap Add to Home screen or Install app.
  3. Confirm by tapping Install.

Shuts itself off at around 3000rpm or when hitting a bump

Hopefully somebody can help me here.

 

The car starts first time everytime from cold. However after she is started, if I hit a bump, it looses power and switches itself off, leaving only the ignition lights, hicas etc on. It then can sometimes take an age to start again.

 

Also if I don't hit a bump or if I approach 3000rpm the same thing can happen. It either switches off or looses power and splutters violently. If I accelerate hard, same thing happens.

 

After it is being drove for a while and the engine has warmed up, it does it less frequently but it still occurs. The problem is it can occur at any stage, even when passing out other cars and that is a nightmare situation and bloody dangerous.

 

I thought that this was a problem with the PTU as I had a series one, but I replaced this at the weekend with a series II and it made no difference whatsoever. I thought it may have been dirty petrol but the filters have just been changed.

 

Any tips anybody or has anybody experienced these symptoms.

Edited by chayden
UPDATE - Problem sorted

Featured Replies

I had a problem with the airflow sensor (MAF) which gave the spluttering sympton approaching 3000 rpm.

  • Author
Sounds like it could be the MAF or the connection to the MAF.

 

Where is the MAF located and I'll have a look and check? Not a mechanic, so forgive this question if it sounds silly.

  • Author
under the slam panel between the head lights.

 

Thanks Legrath and Trebor, I'll check that out and report back.

 

Cheers

Colm

Thanks Legrath and Trebor, I'll check that out and report back.

 

Cheers

Colm

 

Please do! That is, report back! Its always handy to see the resolve of problems like this for any future reference. There are quite a few problem threads on here that never conclude with a solution, so we never know what sorted the particular problem.

Anyway good luck sorting it!

  • Author

Ok guys, I disconnected the MAF sensor, checked it for corrosion, dirt, grim etc but it was clean as a whistle. Put it back and tried the car again, this time revving in neutral. Same thing happened - cut out. When I tried to start it again, it took an age, but for a split second before she finally started, I could here something start to make a sound (pump perhaps?), the light for the engine in orange went off in the dash and it started.

 

The fact that the MAF sensor is clean doesn't mean that it isn't dodgy. I'll get an automotive electrician to check it. I did run the engine with the MAF sensor disconnected and the car wouldn't rev above approximately 2600rpm.

 

Incidentally I never had this problem before I got the car serviced. It is getting worse though. Perhaps the timing is coincidental.

 

Any other suggestions?:confused:

Edited by chayden

mine did the same thing when i had my cambelt changed and it turned out to be the CAS connector that was left unplugged.

  • Author
mine did the same thing when i had my cambelt changed and it turned out to be the CAS connector that was left unplugged.

 

I'll check that . It must be something fairly simple as it was perfect before I got the service done and the belts changed.

Thanks,

Colm

Edited by chayden

the CAS connector is on the front right of the engine,

 

may need to remove the rubber intercooler pipe to get at it.

 

try cleaning the PTU connector, and the temp sesor.

 

youv replaced the PTU, when it may have been the connection.

 

mine was dirty, and i could hear the fuel pump whine from the back of the car.

 

clean the CAS, 2 temp sensors, and 2 PTU connectors.

Just read through this. Talk about confusing :)

 

If the CAS is unplugged your injectors will not fire and you will not be able to start the car let alone rev to 3k rpm.

 

No power above 3000 RPM + lumpy idle will always point directly at the MAF.

Lumpy Idle but full rev range will point at the PTU or the CAS.

  • Author
Just read through this. Talk about confusing :)

 

If the CAS is unplugged your injectors will not fire and you will not be able to start the car let alone rev to 3k rpm.

 

No power above 3000 RPM + lumpy idle will always point directly at the MAF.

Lumpy Idle but full rev range will point at the PTU or the CAS.

 

Thanks to all who have given me some direction and suggestions so far.

 

Just to clarify - I do have power if I accelerate very very slowly through 3000rpm and can go above it. For some reason on normal driving when I approach that magic 3k rpm power drops, splutters etc.. Only thing at any stage it can cut out. If it cuts out when driving and I leave it in gear without clutching it can start again being a manual and has done so.

 

The car is idling high at present around 1200rpm or higher when started initially but after a drive drops below 1000rpm. When I disconnected the MAF sensor and started it the idle rev sat at approximately 1000rpm.

 

I'll have another check on the connections CAS, PTU, MAF sensor, temp sensor etc.. Never did mechanics but by GOD this old Zed will make me learn quite quickly..

  • Author

Went out there tonight to try cleaning the CAS, PTU etc but when I tried to start it, it wouldn't. So that gave me the chance to remove the slam panel and disconnect the MAF. Once I did that - hey presto -it started immediately.

 

I guess that means that the MAF is the problem so I better get a replacement. I couldn't imagine the issue being the wiring back to the management system, because would it not cause problems even with the MAF disconnected? Question rather than statement there guys......

 

And by the way, thanks again to all who have tried to help me out with advise and suggestions.

  • 2 weeks later...
  • Author

I replaced the MAF (2nd hand one from Paul in SWZ parts) and there was definitely an issue with the old one. The car no longer cuts out so I can drive it.

 

Rev it in neutral and no issue. However when driving it still can splutter and can backfire as you go through the rev range. I had changed the PTU to a series II but should I have done anything else. I see mentioned on other posts about resetting the ECU. Would that have been necessary, cause if it is I didn't do it.

  • Author

The ECU was reset and cam connections cleaned after the replacement MAF was installed.

 

Result - Drives perfectly, smooth and powerful.:hyper:

 

Thanks to everybody who gave me pointers.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

Recently Browsing 0

  • No registered users viewing this page.

Important Information

Terms of Use

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.