FAQ
TL;DR: Opel Corsa C 1.0 no-start traced to timing jump; compression measured 10 bar/cyl, “This is not enough.” [Elektroda, robokop, post #16867628]
Why it matters: Quick checks of compression, timing, injectors, and flooding can save an engine from valve damage and costly repairs.
This FAQ is for owners and techs troubleshooting Corsa C 1.0 gasoline engines that crank but won’t start.
Quick Facts
- Low compression flag: 10 bar per cylinder was judged insufficient for reliable start. [Elektroda, robokop, post #16867628]
- Timing-chain service: replace chain, sprockets, guides, and tensioner around 150,000 km to avoid jump. [Elektroda, robokop, post #16867580]
- DTCs P0201–P0203 mean injector circuit faults or commanded fuel cut to prevent wash-down. [Elektroda, woi, post #16867207]
- Backfire through throttle during cranking indicates incorrect valve timing. [Elektroda, grala1, post #16865109]
- Tries to start with pump relay removed = flooded mixture from sensor/MAF issues. [Elektroda, woi, post #16863075]
Why is one spark plug wet while the other two are dry?
A wet plug shows that cylinder is getting fuel but not burning it. Dry plugs suggest no injection or cut-off there. The ECU can disable injectors to prevent cylinder wash-down, logging misfire or injector-circuit faults. Dry or replace the wet plug, then clear codes and retest. “Replace or dry wet candle.” [Elektroda, woi, post #16862765]
What do codes P0201, P0202, and P0203 mean on a Corsa C?
They indicate injector circuit faults on cylinders 1–3 or an ECU-commanded total injection cut. Causes include wiring faults, lack of injector power, or protective shutoff due to flooding. Inspect harness continuity from ECU to injectors and confirm 12 V feed. Clear codes and recheck after cranking. [Elektroda, woi, post #16867207]
Why does my engine try to start only with the fuel pump relay pulled?
That behavior points to an over-rich, flooded condition. A failed coolant temperature sensor reading −40°C or a faulty MAF can make the ECU overfuel. With the pump off, residual fuel leans the mixture enough to catch briefly. Verify sensor readings with a scan tool. [Elektroda, woi, post #16863075]
It blows air back through the throttle while cranking—what does that mean?
Blowback through the throttle strongly indicates incorrect cam-to-crank synchronization. On this engine, a stretched or jumped timing chain can cause intake reversion and a no-start. Inspect timing alignment before extended cranking to avoid valve damage. [Elektroda, grala1, post #16865109]
How do I check compression and what number should I expect?
Perform a wide-open-throttle compression test on all three cylinders with the fuel and spark disabled. The thread’s measured 10 bar per cylinder was deemed too low for a reliable start. Re-test after adding a teaspoon of oil if readings are low, to assess sealing. [Elektroda, robokop, post #16867628]
Could a stretched timing chain cause clatter and a no-start?
Yes. A stretched chain can jump timing, cause clatter, mis-synchronization, and valve contact. Replace the complete timing set—chain, sprockets, guides, and tensioner—rather than the chain alone, especially near 150,000 km. “Replace kpl. timing.” [Elektroda, robokop, post #16867580]
Should I worry about bent valves after a timing jump?
Yes. Piston-to-valve contact is possible once timing slips. Engines may appear to start after electronics repairs, yet still fail from mechanical damage. Inspect valve clearances and leakdown before further driving. Some cases needed full engine replacement after collision. [Elektroda, Pawel wawa, post #16867588]
How do I test injector wiring from the ECU?
Backprobe each injector control wire for continuity from the ECU connector to the injector plug. Check for proper 12 V feed on the common supply and verify ECU pulsing with a noid light. Repair any open or shorted wires before replacing parts. [Elektroda, jerry1960, post #16863564]
Could a blocked exhaust cause a crank-no-start?
Yes. A fully blocked exhaust prevents scavenging, making starting impossible. During cranking, you should feel exhaust flow. Temporarily loosen the system near the manifold or remove the upstream oxygen sensor to create a bypass for testing. [Elektroda, woi, post #16862765]
What does it mean if fuel sprays at the rail but it still won’t start?
Pressure at the bleed indicates delivery to the rail, but mixture, timing, or injector control may still be wrong. With P0201–P0203 active, the ECU might not pulse injectors. Fix electrical faults and verify timing before blaming fuel pressure. [Elektroda, Peugeot407coupe, post #16863143]
How can I safely unflood the Corsa engine?
- Remove all spark plugs; dry or replace any wet plugs.
- Disable fuel; crank 5–10 seconds to clear cylinders, then refit plugs.
- Erase codes; re-enable fuel and attempt start with full throttle (clear-flood). Investigate temp sensor and MAF readings if flooding returns. [Elektroda, woi, post #16862765]
What is a DTC and why does it matter here?
A Diagnostic Trouble Code (DTC) records a detected fault. In this case, injector-circuit DTCs P0201–P0203 point directly to wiring or commanded shutdown. Reading live data alongside DTCs speeds diagnosis and avoids unnecessary parts. [Elektroda, woi, post #16867207]
Does the ECU ever stop all injection during cranking?
Yes. To protect the engine from fuel wash-down, the ECU can totally cut injection if it detects certain errors. This can produce dry plugs on some cylinders and a no-start. Clear faults, fix wiring, and reattempt. [Elektroda, woi, post #16862765]
My chain clatter fades at higher rpm—can I ignore it?
No. Noise reduction with rpm does not mean it is safe. Chain slack can briefly tension with oil pressure, yet still be out of time. Continued running risks valve damage. Replace the complete timing set promptly. [Elektroda, robokop, post #16867580]
What’s a quick triage sequence for this no-start?
Check compression on all cylinders. Verify timing alignment if you hear chain clatter or see throttle blowback. Scan for P0201–P0203; if present, test injector power and continuity, then address flooding causes before further cranking. [Elektroda, woi, post #16867207]
